Information processing method, information processing program, information processing apparatus, and image forming apparatus

ABSTRACT

An information processing method performs steps for an information processing apparatus to communicate with an image forming apparatus having first and second sheet output sections. The second sheet output section can be switched between a close position to serve to guide a sheet to the first sheet output section, and an open position not to guide the sheet to the first sheet output section but to stack the sheet. The method inputs a type of sheet, acquires information indicating whether the second sheet output section is in an open or closed state, and transmits image information to the image forming apparatus. When the sheet type recommends the sheet be output to the second sheet output section and the second sheet output section is in the closed state, a message is output to prompt to switch the second sheet output section into the open position before the image information is transmitted.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 17/200,662, filed on Mar. 12, 2021, which claims priority fromJapanese Patent Application No. 2020-045742, filed Mar. 16, 2020,Japanese Patent Application No. 2020-056557, filed Mar. 26, 2020,Japanese Patent Application No. 2020-087708, filed May 19, 2020,Japanese Patent Application No. 2020-101025, filed Jun. 10, 2020, andJapanese Patent Application No. 2020-123116, filed Jul. 17, 2020, whichare hereby incorporated by reference herein in their entirety.

BACKGROUND Field

The present disclosure relates to an information processing method foran information processing apparatus capable of communicating with animage forming apparatus, an information processing program, aninformation processing apparatus, and an image forming apparatus.

Description of the Related Art

Japanese Patent Laid-Open No. 2015-110455 describes a configurationincluding a plurality of sheet output trays in an image formingapparatus, such as a laser beam printer, that forms an image.

For example, in the case where an image is formed on the upper surfaceof a sheet, there is a sheet output tray that is a sheet output sectionto which, when a sheet on which an image has been formed moves along aconveying path, the sheet turned upside down is output such that thesurface having the image faces downward. Where the surface having animage is referred to as face, the sheet output tray is referred to asface-down (hereinafter, also referred to as FD) tray because a sheet isoutput so as to face downward. On the other hand, for example, in thecase where an image is formed on the upper surface of a sheet, there isa sheet output tray that is a sheet output section to which, when asheet on which the image has been formed moves along a conveying path,the sheet not turned upside down is output such that the surface havingthe image faces upward. The sheet output tray is referred to as face-up(hereinafter, also referred to as FU) tray because a sheet is output soas to face upward.

The FU tray can be arranged to be openable. In this configuration, whenthe FU tray is closed, the FU tray serves as a guiding portion of theconveying path to the FD tray; whereas, when the FU tray is open, the FUtray serves as not a guiding portion of the conveying path to the FDtray but a sheet output tray capable of carrying sheets.

A user is able to select one of the sheet output sections according tousage. When the sheet output section selected by the user does notaccord with an open/closed state of the FU tray, the open/closed stateof the FU tray is informed to the user.

However, an image forming apparatus does not necessarily allowdesignation of a sheet output section. When a sheet output section isnot allowed to be designated, providing information as described inJapanese Patent Laid-Open No. 2015-110455 cannot be performed. In such asituation, it is desired to inform a message to prompt to switch theopen/closed state of the FU tray.

SUMMARY

According to an aspect of the present disclosure, an informationprocessing method for an information processing apparatus, wherein theinformation processing apparatus is to communicate with an image formingapparatus having an image forming unit arranged to form an image on asheet, and having first and second sheet output sections, eachconfigured to receive output of the sheet having the image formed on thesheet, wherein, when conveyed along a first sheet output conveying path,the sheet is output to the first sheet output section so that the imagefaces downward and, when conveyed along a second sheet output conveyingpath, the sheet is output to the second sheet output section so that theimage faces upward, and wherein the second sheet output section iscapable of being switched between a close position to serve as a guidingportion arranged to guide the sheet to the first sheet output section,and an open position to serve as a sheet output section arranged not toguide the sheet to the first sheet output section but to be capable ofstacking the sheet, includes inputting a type of sheet, acquiringinformation indicating whether the second sheet output section is in anopen state or in a closed state, transmitting image information to theimage forming apparatus, and outputting a message, wherein, when theinput type of sheet is a sheet recommended to be output to the secondsheet output section and the acquired information indicates that thesecond sheet output section is in the closed state, outputting includesoutputting a message to prompt to switch the second sheet output sectioninto the open position before the image information is transmitted tothe image forming apparatus.

Further features of the present disclosure will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of an image forming apparatusin a first embodiment.

FIG. 2A is a diagram showing an example of a radius of curvature of aconveying path from a sheet feeding cassette and an example of a radiusof curvature of a conveying path from an MP tray.

FIG. 2B is a diagram showing an example of a radius of curvature of aconveying path to an FU tray and an example of a radius of curvature ofa conveying path to an FD tray.

FIG. 3A is a control block diagram of a whole printer control system inthe first embodiment.

FIG. 3B is a control block diagram of hardware concerned with sheetconveyance control in the first embodiment.

FIG. 4A is a configuration diagram of a printing process.

FIG. 4B is a block diagram showing the functions of an application inthe first embodiment.

FIG. 5A is a table for paper type selection in the first embodiment.

FIG. 5B is a table for printing operation (double-sided printing orsingle-sided printing) in the first embodiment.

FIG. 5C is a table for a sheet output section (FD output or FU output)in the first embodiment.

FIG. 6A to FIG. 6F are views illustrating messages in the firstembodiment.

FIG. 7A and FIG. 7B are flowcharts of a process in the first embodiment.

FIG. 8A and FIG. 8B are flowcharts of a process in a second embodiment.

FIG. 9A is an advanced settings screen for printing operation.

FIG. 9B is a message window that appears when FU output recommendedpaper is selected.

FIG. 10 is a block diagram showing the functions of a printer controllerin a third embodiment.

FIG. 11A and FIG. 11B are flowcharts of a process in the thirdembodiment.

FIG. 12A and FIG. 12B are flowcharts of a process in a fourthembodiment.

FIG. 13A and FIG. 13B are views illustrating messages in fifth and sixthembodiments.

FIG. 14A to FIG. 14F are views illustrating messages in the fifth andsixth embodiments.

FIG. 15A is a flowchart of a process in the fifth embodiment.

FIG. 15B is a flowchart of the process in the fifth embodiment.

FIG. 16A is a flowchart of a process in the sixth embodiment.

FIG. 16B is a flowchart of the process in the sixth embodiment.

FIG. 17A is a flowchart of a process in a seventh embodiment.

FIG. 17B is a flowchart of the process in the seventh embodiment.

FIG. 18 is a schematic configuration diagram of an image formingapparatus.

FIG. 19A is a control block diagram of a whole printer control system inan eighth embodiment.

FIG. 19B is a control block diagram of hardware concerned with sheetconveyance control in the eighth embodiment.

FIG. 20A to FIG. 20C are views illustrating an FU tray open/closesensor.

FIG. 20D is a view illustrating a method of detecting a sheet in aconveying path.

FIG. 21A is the stacking order of sheets output to an FD tray.

FIG. 21B is the stacking order of sheets output to an FU tray.

FIG. 21C is a diagram when the stacking order of sheets output to the FUtray is sorted.

FIG. 22 is a flowchart of a process in the eighth embodiment.

FIG. 23A to FIG. 23E are views illustrating messages in the eighth totenth embodiments.

FIG. 24 is a flowchart of a process in the ninth embodiment.

FIG. 25 is a flowchart of a process in the tenth embodiment.

FIG. 26A and FIG. 26B are diagrams for a sheet conveying position.

FIG. 26C and FIG. 26D are diagrams for a sheet conveying position.

FIG. 26E and FIG. 26F are diagrams for a sheet conveying position.

FIG. 26G and FIG. 26H are diagrams for a sheet conveying position.

FIG. 27A and FIG. 27B are flowcharts of a process in an eleventhembodiment.

FIG. 28A and FIG. 28B are flowcharts of a process in a twelfthembodiment.

FIG. 28C is a flowchart of the process in the twelfth embodiment.

FIG. 29A to FIG. 29D are views illustrating messages in the eleventh tofourteenth embodiments.

FIG. 30A, and FIG. 30D to FIG. 30F, are views illustrating messages inthe thirteenth embodiment.

FIG. 30B is a view illustrating the sequence of image signals output inautomatic double-sided printing mode.

FIG. 30C is a view illustrating the sequence of image signals output inmanual double-sided printing mode.

FIG. 31A and FIG. 31B are flowcharts of a process in the thirteenthembodiment.

FIG. 32A and FIG. 32B are flowcharts of a process in the fourteenthembodiment.

FIG. 32C is a flowchart of the process in the fourteenth embodiment.

FIG. 33A to FIG. 33C are views illustrating movement of a sheet in afifteenth embodiment.

FIG. 33D to FIG. 33F are views illustrating movement of a sheet in thefifteenth embodiment.

FIG. 33G to FIG. 33I are views illustrating movement of a sheet in thefifteenth embodiment.

FIG. 33J to FIG. 33M are views illustrating movement of a sheet in thefifteenth embodiment.

FIG. 34A and FIG. 34B are flowcharts of a process for a sheet outputconveyance malfunction.

FIG. 34C and FIG. 34D are flowcharts of a process for a sheet outputconveyance malfunction.

FIG. 35A and FIG. 35B are flowcharts of a process for a sheet feedconveyance malfunction.

FIG. 35C and FIG. 35D are flowcharts of a process for a sheet feedconveyance malfunction.

FIG. 36A and FIG. 36B are flowcharts of a process for a double-sidedprinting conveyance malfunction.

FIG. 36C and FIG. 36D are flowcharts of a process for a double-sidedprinting conveyance malfunction.

FIG. 37A to FIG. 37D are views illustrating messages output by a messageoutput unit in the fifteenth embodiment.

FIG. 37E to FIG. 37I are views illustrating messages output by themessage output unit in the fifteenth embodiment.

FIG. 38A is a schematic diagram of an image forming apparatus in asixteenth embodiment.

FIG. 38B is a control block diagram of hardware concerned with sheetconveyance control in the sixteenth embodiment.

FIG. 38C to FIG. 38F are diagrams for a lock unit and an FU tray.

FIG. 39A and FIG. 39B are flowcharts of a process in the sixteenthembodiment.

DESCRIPTION OF THE EMBODIMENTS First Embodiment

Hereinafter, an embodiment of the present disclosure will be describedwith reference to the attached drawings. The following embodiment doesnot limit the disclosures described in the appended claims, and not allthe combinations of characteristics described in the embodiment areindispensable for the solution of the present disclosure.

Image Forming Process

FIG. 1 is a schematic configuration diagram of an image formingapparatus 10 of the present embodiment.

Initially, an image forming unit that performs an image forming processwill be described. In FIG. 1 , a photosensitive drum 122 is made up ofan organic photoreceptor or an amorphous silicon photoreceptor and isdriven to rotate at a predetermined circumferential velocity (processspeed) in a clockwise direction. The peripheral surface of thephotosensitive drum 122 is electrically charged uniformly with apredetermined polarity and potential by a charging roller 123. When alaser beam output from an optical device 109 is reflected by a laserreflecting mirror 108 and irradiated to the peripheral surface of theelectrically charged photosensitive drum 122, exposure is performed. Anelectrostatic latent image is formed through the exposure.

The outline of image processing for forming an electrostatic latentimage will be described with reference to FIG. 3A and FIG. 3B.Initially, a printer controller 213 modulates (on/off conversion) imageinformation input from a host computer 200 to an image signal. Theprinter controller 213 transmits the image signal to an enginecontroller 301. The optical device 109 emits a laser beam in accordancewith the image signal. The image information here is referred to asfirst image information hereinafter, and the image signal is referred toas second image information. The first image information and the secondimage information have been described as different ones; however, thefirst image information and the second image information may be thesame.

An electrostatic latent image formed on the photosensitive drum 122 incorrespondence with an intended image in this way is developed by adeveloping machine 121 as a toner image when toner electrically chargedwith the same polarity as the electric charge generated by the chargingroller 123 adheres to the electrostatic latent image. Forming anelectrostatic latent image is started when the leading edge of a sheetis detected by a registration sensor 106.

As described above, components concerned with a series of image formingprocess of forming an image on a sheet are referred to as image formingunit. Components concerned with feeding of a sheet to the image formingunit are referred to as sheet feeding unit. Next, the sheet feeding unitwill be described. One of sheets stacked in a sheet feeding cassette 100is picked up by a sheet feeding roller 102 and fed to a pair ofconveying rollers 104 one by one by a pair of separation rollers 103. Atthis time, the presence or absence of sheets in the sheet feedingcassette 100 is detected by a sheet detecting sensor 101. The sheet fedto the pair of conveying rollers 104 is conveyed to a pair of conveyingrollers 105. At this time, one of sheets stacked in the sheet feedingcassette 100 is fed through a sheet feed conveying path along which asheet is conveyed to the pair of conveying rollers 105 such that anupper surface in a stacked state faces downward. The sheet feedconveying path at this time is also referred to as first sheet feedconveying path. The sheet feeding cassette 100 is also referred to asfirst sheet feeding section.

A toner image developed on the photosensitive drum 122 is transferred tothe sheet. At this time, a transfer roller 107 supplies electric chargewith reverse polarity to toner from the rear surface of the sheet totransfer the toner image from the photosensitive drum 122 to the sheet.The sheet to which the toner image is transferred in this way isseparated from the photosensitive drum 122 and conveyed to a fixingdevice 130. The fixing device 130 is made up of a heater 132, athermistor 131 that detects the temperature of the heater 132, a fixingroller 133, and a pressure roller 134. The fixing device 130 fixes thetoner image on the sheet by means of heat generated by the heater 132and pressure applied by a fixing nip made up of the fixing roller 133and the pressure roller 134.

Subsequently, the case where a sheet is fed from a multi-purpose tray(MP tray) 140 for feeding a sheet manually as another sheet feedingsection will be described. The MP tray 140 is an opening/closing membercapable of being switched between an open position and a close position.When the MP tray 140 is in the close position, the MP tray 140 serves asa sheet feeding port for feeding a sheet. When the MP tray 140 is in theclose position, the MP tray 140 does not serve as a sheet feeding portfor feeding a sheet. When sheets are fed from the MP tray 140, the MPtray 140 is switched into the open position, and sheets are stacked. TheMP tray 140 is also referred to as second sheet feeding section. Whensheets are fed from the MP tray 140, the MP tray 140 is brought into theopen state, and sheets are stacked. An MP sheet feeding roller 142conveys sheets stacked on the MP tray 140 to a pair of MP separationrollers 143. The pair of MP separation rollers 143 separates one of theconveyed sheets and conveys the separated sheet to the pair of conveyingrollers 105. The sheet fed to the pair of conveying rollers 105 isconveyed to the photosensitive drum 122. After the sheet is conveyed tothe photosensitive drum 122, a toner image is formed and fixed onto thesheet as in the case of a sheet fed from the sheet feeding cassette 100and is then output to an FU tray 116 or an FD tray 115. At this time, asheet stacked on the MP tray 140 is fed along a sheet feed conveyingpath along which the sheet is conveyed to the pair of conveying rollers105 such that the upper surface of the sheet in a stacked state facesupward. The sheet feed conveying path at this time is also referred toas second sheet feed conveying path. The MP tray 140 at this time isalso referred to as second sheet feeding section.

In the present embodiment, the case where the MP tray 140 is manuallyopened or closed is described. Alternatively, the MP tray 140 may beautomatically opened or closed. In this case, the MP tray 140 isautomatically opened or closed by a driving source like an MP trayopen/close motor 331 and an MP tray open/close motor input circuit 319shown in FIG. 3B.

The first sheet feed conveying path and the second sheet feed conveyingpath have different radii of curvature. The radius of curvature of eachof the sheet feed conveying paths will be described by using theschematic cross-sectional view of the image forming apparatus of FIG. 2Aand examples of specific numeric values. FIG. 2A shows that the MP tray140 is in the open state. When a sheet is fed from the sheet feedingcassette 100, a sheet is conveyed along a conveying path that passesthrough the pair of separation rollers 103 and then passes through thepair of conveying rollers 104. The radius of curvature of the conveyingpath is, for example, R80 (80 mm). On the other hand, when a sheet isfed from the MP tray 140, a sheet is conveyed along a conveying paththat passes through the pair of MP separation rollers 143 and thenpasses through the pair of conveying rollers 105. The radius ofcurvature of the conveying path is, for example, R800 (800 mm). Here,the conveying path from the sheet feeding cassette 100 and the conveyingpath from the MP tray 140 are compared with each other by using examplesof numeric values of the radii of curvature. It is assumed that aminimum value of the radius of curvature of the conveying path in thecase where a sheet is fed from the sheet feeding cassette 100 is lessthan a minimum value of the radius of curvature of the conveying path inthe case where a sheet is fed from the MP tray 140.

For this reason, when, for example, a sheet of stiff paper, such asthick paper and envelope, is fed from the sheet feeding cassette 100, asheet passes along the conveying path with a small radius of curvature,so the conveyance resistance is large and, as a result, a conveyancemalfunction or a paper jam may occur. Accordingly, when such a sheet isfed from the MP tray 140, the sheet is not conveyed along the conveyingpath with a small radius of curvature, so a conveyance malfunction or apaper jam is reduced.

Subsequently, sheet output sections will be described. The image formingapparatus 10 includes the FD tray 115 to which a sheet is output facedown (hereinafter, also referred to as FD output) and the FU tray 116 towhich a sheet is output face up (hereinafter, also referred to as FUoutput). The sheet output conveying paths to the respective sheet outputtrays are different.

The sheet output conveying path to the FD tray 115 is a conveying pathalong which a sheet is conveyed from a set of FU rollers 111, passesthrough a pair of FD rollers 112 and is then stacked on the FD tray 115.The sheet output conveying path to the FD tray 115 is also referred toas first sheet output conveying path. When a sheet having an image onits upper surface is conveyed along the first sheet output conveyingpath, the sheet is FD output to the FD tray 115 such that the imagesurface faces downward (face down) (FD).

The FU tray 116 is an opening/closing member capable of being switchedbetween an open position and a close position. When the FU tray 116 isin the close position, the FU tray 116 serves as a guiding portion thatguides a sheet to the FD tray 115. When the FU tray 116 is in the openposition, the FU tray 116 serves as not a guiding portion that guides asheet to the FD tray 115 but a sheet output tray capable of carryingsheets.

The sheet output conveying path to the FU tray 116 is a conveying pathalong which a sheet is conveyed from the set of FU rollers 111 and isstacked on the FU tray 116. The sheet output conveying path to the FUtray 116 is also referred to as second sheet output conveying path. Whena sheet having an image on its upper surface is conveyed along thesecond sheet output conveying path, the sheet is FU output to the FUtray 116 such that the image surface faces upward (face up) (FU).

An FU tray open/close sensor 117 is an open/close signal output unitthat outputs a first signal in the closed state of the FU tray 116 andthat outputs a second signal in the open state. A CPU 302 detects theopen/closed state in accordance with the first signal or second signaloutput from the FU tray open/close sensor 117. In other words, the FUtray open/close sensor 117 functions as a detection unit that detectswhether the FU tray 116 is in the open state or in the closed state. Thedetailed function will be described later.

In the present embodiment, the FU tray 116 is not necessarily anopening/closing member capable of being switched between the openposition and the close position. For example, a member, such as aflapper, may be used to control whether to FD output a sheet to the FDtray 115 or FU output a sheet to the FU tray 116.

The first sheet output conveying path and the second sheet outputconveying path have different radii of curvature. The radius ofcurvature of each of the sheet output conveying paths will be describedby using the schematic cross-sectional view of the image formingapparatus of FIG. 2B and examples of specific numeric values. In FIG.2B, the open state of the FU tray 116 is represented by the dashed line.When the FU tray 116 is in the closed state, a sheet is conveyed along aconveying path along which, as represented by the continuous line inFIG. 2B, the sheet passes through the set of FU rollers 111 and thenpasses through the pair of FD rollers 112, and is then output to the FDtray 115. The radius of curvature of the conveying path is, for example,R75 (75 mm). On the other hand, when the FU tray 116 is in the openstate, a sheet passes through the set of FU rollers 111, then conveyedalong a conveying path represented by the dashed line in FIG. 2B, andoutput to the FU tray 116. The radius of curvature of the conveying pathis, for example, R400 (400 mm). Here, the conveying path to the FD tray115 and the conveying path to the FU tray 116 are compared with eachother by using examples of numeric values of the radii of curvature. Itis assumed that a minimum value of the radius of curvature of the sheetconveying path formed in the case where the FU tray 116 is in the closedstate is less than a minimum value of the radius of curvature of thesheet conveying path formed in the case where the FU tray 116 is in theopen state.

For this reason, when, for example, a sheet of stiff paper, such asthick paper and envelope, is FD output, a sheet passes along theconveying path with a small radius of curvature in a state where heatreceived from the heater 132 remains in the sheet, so the sheet may becurled. In addition, when the radius of curvature of a conveying path issmall, the conveyance resistance is large and, as a result, a conveyancemalfunction or a paper jam may occur. Accordingly, when the FU tray 116is in the open state, a sheet is not conveyed along the conveying pathwith a small radius of curvature, so the curling of a sheet is reduced.

Referring back to FIG. 1 , an after-fixing paper presence sensor 110 isprovided before the set of FU rollers 111. When double-sided printing isperformed, after a lapse of a predetermined time from when the trailingedge of a fixed sheet passes through the after-fixing paper presencesensor 110, the rotational direction of the pair of FD rollers 112 isreversed, and the sheet is conveyed to a double-sided printing conveyingpath L1 by the pair of FD rollers 112. The sheet conveyed to thedouble-sided printing conveying path L1 is fed again by a pair ofdouble-sided printing conveying rollers 114 and conveyed to the pair ofconveying rollers 105 again. A toner image is transferred to the backsurface of the sheet conveyed again to the pair of conveying rollers 105and fixed, and then the sheet is output to the FD tray 115.

In this way, when double-sided printing is performed, a sheet passesalong the conveying path with a small radius of curvature in a statewhere heat received from the heater 132 remains in the sheet as in thecase of FD output. For this reason, when, for example, a sheet of stiffpaper, such as thick paper and envelope, is used for double-sidedprinting, a sheet may be curled. Therefore, for example, a sheet ofstiff paper, such as thick paper and envelope, is not recommended fordouble-sided printing. If the FU tray 116 is in the open state in thecase of double-sided printing, the conveying path from the set of FUrollers 111 to the pair of FD rollers 112 disappears, with the resultthat double-sided printing cannot be performed.

In the present embodiment, the case where the FU tray 116 is manuallyopened or closed is described. Alternatively, the FU tray 116 may beautomatically opened or closed. In this case, the FU tray 116 isautomatically opened or closed by a driving source like an FU trayopen/close motor 330 and an FU tray open/close motor input circuit 320shown in FIG. 3B. Automatic open/close will be described later.

Configuration of Printer Control System

FIG. 3A is a block diagram that illustrates the configuration of a wholeprinter control system of the present embodiment. As long as thefunctions of the present embodiment are implemented, the presentembodiment is applicable to a stand-alone device or a system made up ofa plurality of devices or a system connected via a network, such as aLAN and a WAN, to execute processes.

In FIG. 3A, the host computer 200 includes a CPU 201. The CPU 201processes documents mixedly containing graphics, images, characters,tables (including spreadsheets or the like), and the like in accordancewith a document processing program or the like stored in a program ROMof a ROM 203 or an external memory 210. In the present embodiment, theCPU 201 processes image information by using an application 401, agraphics engine 402, and a printer driver 403 as shown in, for example,FIG. 4A. The detailed process will be described later.

The CPU 201 generally controls devices connected to a main bus 204. Theprogram ROM of the ROM 203 or the external memory 210 stores anoperating system program (hereinafter, OS) or the like that is a controlprogram for the CPU 201. A font ROM of the ROM 203 or the externalmemory 210 stores font data or the like to be used in the documentprocessing. A data ROM of the ROM 203 or the external memory 210 storesvarious data to be used in the document processing. A RAM 202 functionsas a main memory, a work area, and the like for the CPU 201.

A key controller 205 controls key input from a keyboard 208 or apointing device (not shown). A display controller 206 controls displayon a display 209. A user performs an operation, such as selecting aprinting operation, with the keyboard 208 or the pointing device (notshown) as an input unit. Thus, the user inputs a desired printingoperation to the host computer 200.

A disk controller 207 controls access to the external memory 210. Theexternal memory 210 is a hard disk drive (HD), a flexible disk (FD), orthe like. The external memory 210 stores a boot program, variousapplications, font data, user files, edit files, a printer controlcommand generation program (hereinafter, printer driver), and the like.

The CPU 201, for example, executes a process of rasterizing an outlinefont onto a display information RAM set on the RAM 202. The rasterizingprocess enables WYSIWYG (What You See Is What You Get) on the display209. WYSIWYG is such that the CPU 201 displays a final finished image onthe display 209 to allow a user to edit the final finished image whilechecking the final finished image. The CPU 201 also executes variousdata processing by opening various windows registered in accordance withcommands issued from a user with a mouse cursor or the like (not shown)on the display 209. When a user performs printing, the user opens awindow for print settings and sets a print processing method for theprinter driver, including a setup of a printer and selecting a printmode. Image information generated through such a process is output fromthe host computer 200 to a printer 212.

The printer 212 is the image forming apparatus 10 shown in FIG. 1 . Theprinter 212 forms an image on a sheet by using the image informationinput from the host computer 200 in accordance with the above-describedelectrophotographic process. The printer controller 213 is controlled bythe CPU 214. The CPU 214 outputs an image signal that is second imageinformation to a printing section (printer engine) 221, connected to themain bus 204, in accordance with a control program or the like stored ina program ROM of a ROM 216. The program ROM of the ROM 216 stores thecontrol program or the like for the CPU 214. A font ROM of the ROM 216stores font data or the like to be used in generating the outputinformation. A data ROM of the ROM 216 stores information or the like tobe used on the host computer 200.

The CPU 214 is capable of communicating information with the hostcomputer 200 by using a bidirectional interface (interface) 211 via aninput section 218 and provides information or the like in the printer212 to the host computer 200. At this time, the input section 218functions as a reception unit that receives information including, forexample, first image information or the like from the host computer 200.

A RAM 215 functions as a main memory, a work area, and the like for theCPU 214 and is configured such that a memory capacity can be increasedby using an optional RAM (not shown) connected to an expansion port (notshown). The RAM 215 is used as an output information expansion area, anenvironmental data storage area, an NVRAM, or the like. Switches, LEDindicators, and the like for operation are arranged on an operationpanel 222.

An external memory (not shown) may be connected to the printer 212 inthe present embodiment as an option. The external memory (not shown)stores font data, an emulation program, form data, and the like. Inaddition to internal fonts, an optional card or a plurality of externalmemories (not shown) storing a program that interprets printer controllanguages of different language systems may be connected to the printer212 in the present embodiment.

FIG. 3B is a block diagram showing the configuration of hardwareconcerned with sheet conveyance control as a software functionimplemented by the printing section 221 of the present embodiment. Theprinting section 221 is controlled by the CPU 302. The CPU 302 controlsthe printing section 221 in accordance with a computer program stored ina ROM 303 and a RAM 304 that function as a storage section.Alternatively, the CPU 302 and an MPU (not shown) may include aplurality of processors, such as multi-cores, and may control theprinting section 221 with the plurality of processors.

A storage section in the engine controller 301 is made up of one or morememories such as the ROM 303 and the RAM 304 and stores various piecesof information including a computer program for performing variousoperations (described later), communication parameters for wirelesscommunication, and the like. The storage section in the presentembodiment may be a memory, such as the ROM 303 and the RAM 304. Thestorage section in the present embodiment may be, for example, a storagemedium, such as a flexible disk, a hard disk drive, an optical disk, amagneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatilememory card, and a DVD.

The CPU 302 communicates with the ROM 303, the RAM 304, and an I/O port306 via a communication bus 305. The CPU 302 executes a program storedin the ROM 303, acquires a calculated result during execution, and savesthe calculated result in the RAM 304. The CPU 302 also controls theprinting section 221 in accordance with a program stored in the ROM 303.

The drive of a conveying motor 321 is controlled via a conveying motordriving circuit 311 and the I/O port 306. The conveying motor 321 drivesthe photosensitive drum 122, the pair of conveying rollers 105, and thepair of double-sided printing conveying rollers 114 for rotation. Theconveying motor 321 is also a driving source for the sheet feedingroller 102 and the pair of separation rollers 103. The conveying motor321 drives the sheet feeding roller 102 and the pair of separationrollers 103 when a sheet feeding solenoid 322 turns on. The conveyingmotor 321 is also a driving source for the MP sheet feeding roller 142and the pair of MP separation rollers 143. The conveying motor 321drives the MP sheet feeding roller 142 and the pair of MP separationrollers 143 when an MP tray solenoid 328 turns on. The sheet feedingsolenoid 322 is switched between an on state and an off state via asheet feeding solenoid driving circuit 312 and the I/O port 306.

A double-sided printing motor 323 is driven via a double-sided printingmotor driving circuit 313 and the I/O port 306 and drives the pair of FDrollers 112 for rotation. The drive of a sheet output motor 324 iscontrolled via a sheet output motor driving circuit 314 and the I/O port306. The sheet output motor 324 drives the fixing roller 133 andpressure roller 134 of the fixing device 130 and the set of FU rollers111 for rotation. The MP tray solenoid 328 is switched between an onstate and an off state via an MP tray solenoid driving circuit 318 andthe I/O port 306.

A paper presence detection result detected by the after-fixing paperpresence sensor 110 is transmitted to the CPU 302 via a fixing sensorinput circuit 316 and the I/O port 306. The open/closed state of the FUtray 116, detected by the FU tray open/close sensor 117, is transmittedto the CPU 302 via an FU tray open/close sensor input circuit 317 andthe I/O port 306.

The drive of an FU tray open/close motor 330 is controlled via an FUtray open/close motor input circuit 320 and the I/O port 306. The FUtray open/close motor 330 drives the FU tray 116 for opening or closing.Similarly, the drive of an MP tray open/close motor 331 is controlledvia an MP tray open/close motor input circuit 319 and the I/O port 306.The MP tray open/close motor 331 drives the MP tray 140 for opening orclosing.

With the components described with reference to FIG. 3A and FIG. 3B, thehost computer 200 transmits information on image formation to theprinter 212 in accordance with an instruction from the CPU 201.Information on image formation, transmitted from the host computer 200to the printer 212, includes a type of sheet on which an image is formed(hereinafter, referred to as paper type) and a selected status ofdouble-sided printing or single-sided printing. The printer 212 performsan image forming process in accordance with the information on imageformation, received from the host computer 200. The printer 212 thatperforms such an image forming process and the host computer 200 may becollectively referred to as image forming system.

At this time, the host computer 200 is, for example, an informationprocessing apparatus, such as a PC and a smartphone, and is capable ofcommunicating with the printer 212.

Block Chart Showing Printing Process

FIG. 4A is a block chart showing a printing process in the host computer200 to which a printing apparatus, such as a printer, is directlyconnected or connected via a network. The printing process that isexecuted by the CPU 201 on the host computer 200 to which the printer212 of the present embodiment is connected will be described withreference to FIG. 4A.

The application 401, the graphics engine 402, the printer driver 403,and the application 404 are present as files saved in the externalmemory 210. These files are program modules that are loaded onto the RAM202 by the OS or a module that uses those modules and executed by theCPU 201. The application 401 and the printer driver 403 can be added toan FD or a CD-ROM (not shown) that is the external memory 210 or an HDthat is an external memory (not shown) of the printer 212 via a network(not shown).

For example, the application 401 saved in the external memory 210 isloaded onto the RAM 202 by the OS and is executed by the CPU 201. Whenthe CPU 201 performs a printing process by using the application 401,the CPU 201 executes the graphics engine 402, which is executable whenloaded onto the RAM 202 by the OS, to output (draw) the above-describedfirst image information. When the CPU 201 outputs (draws) the firstimage information by using the graphics engine 402, the OS loads theprinter driver 403 prepared for each printer from the external memory210 onto the RAM 202 and makes the printer driver 403 executable.

Subsequently, the case where the CPU 201 sets the output of theapplication 401 to the printer driver 403 will be described. The CPU 201outputs a graphic device interface (GDI) function output from theapplication 401 to the graphics engine 402. The CPU 201 converts the GDIfunction to a device driver interface (DDI) function by using thegraphics engine 402 and then outputs the DDI function to the printerdriver 403. The CPU 201 converts the DDI function output from thegraphics engine 402 to, for example, a page description language (PDL)by using the printer driver 403. A PDL is a control command that can berecognized by the printer controller 213 of the printer 212.

The CPU 201 executes the application 404 loaded onto the RAM 202 by theOS to output a printer control command converted by the printer driver403 to the input section 218 of the printer controller 213 as firstimage information. At this time, the first image information isconverted to, for example, an image signal or the like before beingoutput from the printer controller 213 to the printing section 221. Theimage signal is second image information used to draw an electrostaticlatent image by turning on or off laser.

FIG. 4B is a block diagram showing functions in the case where a programof the application 404 is loaded onto the RAM 202 by the OS and isexecuted by the CPU 201. The application 404 mainly functions as a UIsection 405, a setting section 406, and a transmission and receptionsection 407.

When the application 404 functions as the UI section 405, the UI section405 functions as an output unit. When the UI section 405 functions asthe output unit, the UI section 405 displays on the display 209information used for a user to complete input of information on imageformation. At this time, when, for example, a user inputs information onimage formation by a combination (described later), the UI section 405displays an alarm (hereinafter, also referred to as message) set by thesetting section 406 on the display 209. The message displayed at thistime may be, for example, any one of the message contents shown in FIG.6B, displayed on the display 209 as shown in FIG. 6C to FIG. 6F. Thesemessages are not necessarily displayed on the display 209.Alternatively, the message contents shown in FIG. 6B may be informed toa user by voice by means of, for example, a reading function.Alternatively, for example, the message contents shown in FIG. 6B may beinformed to a user by light emitting patterns of an LED lamp.

When the application 404 functions as the setting section 406, theapplication 404 sets a flag when, for example, a user inputs informationon image formation by a combination (described later). The UI section405 displays a message on the display 209 in accordance with the flag.The combination is specifically a combination of information about apaper type input by a user, a selected status of double-sided printingor single-sided printing, and a selected status of sheet output section.

When the application 404 functions as the transmission and receptionsection 407, the application 404 communicates information between thehost computer 200 and the printer controller 213. The transmission andreception section 407 functions as a transmission unit in thiscommunication and transmits information on image formation (alsoreferred to as print job) to the printer controller 213. A transmissionstep of a print job is executed, for example, after a user completesadvanced settings for printing operation and closes the advancedsettings screen for printing operation. A print job is transmitted fromthe host computer 200 to the printer controller 213 in a secondtransmission step, and the input section 218 that is a reception unitreceives the print job.

Sheet of Stiff Paper, Such as Thick Paper and Envelope, and FD Output/FUOutput and Double-Sided Printing

In the image forming apparatus 10 in the present embodiment, the radiusof curvature of the conveying path from the set of FU rollers 111,located just downstream of the fixing device 130, to the FD tray 115 issmall. For this reason, when, for example, a sheet of stiff paper, suchas thick paper and envelope, is output from the FD tray 115 or subjectedto double-sided printing, the sheet passes along the conveying path witha small radius of curvature before heat remaining in the sheet coolsdown, so the sheet tends to be curled. For the above reason, forexample, a sheet of stiff paper, such as thick paper and envelope, isdesirably FU output to the FU tray 116 along the conveying path with alarge radius of curvature rather than being FD output to the FD tray 115along the conveying path with a small radius of curvature. For example,a sheet of stiff paper, such as thick paper and envelope, is desirablynot conveyed along the conveying path with a small radius of curvaturefor double-sided printing.

Accordingly, in the present embodiment, the curling of a sheet asdescribed above is reduced. For this purpose, the UI section 405 informsa message to a user according to paper type information included ininformation on image formation, input by the user, and a selected statusof double-sided printing or single-sided printing.

In the present embodiment, paper having a basis weight of greater thanor equal to 200 g/m² is described as thick paper. If thick paper issubjected to double-sided printing or output to the FD tray 115 alongthe conveying path with a small radius of curvature, a sheet may behighly likely to be curled for the above-described reason. On the otherhand, when paper having a basis weight of less than 200 g/m²(hereinafter, referred to as plain paper), even when a sheet issubjected to double-sided printing or output to the FD tray 115 alongthe conveying path with a small radius of curvature, the sheet is lesslikely to be curled.

For the above reason, in the present embodiment, for example, a sheet ofstiff paper, such as thick paper and envelope, is defined as FU outputrecommended paper recommended to be output to the FU tray 116. At thetime of selecting a paper type as shown in FIG. 5A, FU outputrecommended paper is defined as a paper type of 2, and plain paper thatmay be output to not only the FU tray 116 but also the FD tray 115(other than FU output recommended paper) is defined as a paper typeof 1. Examples of the FU output recommended paper include thick paper,envelope, label paper, glossy paper, and gloss paper. In the presentembodiment, as shown in FIG. 5B, for selecting double-sided printing orsingle-sided printing in a print job, single-sided printing is definedas a printing operation of 1, and double-sided printing is defined as aprinting operation of 2. Furthermore, in the present embodiment, asshown in FIG. 5C, for selecting the sheet output section in a print job,FD output (a sheet is output to the FD tray 115) is defined as a sheetoutput section of 1, and FU output (a sheet is output to the FU tray116) is defined as a sheet output section of 2.

Combination of Print Job and Open/Closed State of FU Tray 116, andMessage Content Displayed

Hereinafter, paper type information, a selected status of double-sidedprinting or single-sided printing, and an open/closed state of the FUtray 116, acquired by the transmission and reception section 407, and amessage content displayed on the display 209 of the host computer 200will be described with reference to FIG. 6A to FIG. 6F. Detailedprocesses at the time when the setting section 406 actually selects andsets a message will be described later.

When a user designates FU output recommended paper, double-sidedprinting is not performed because of the above-described reason, so,even when the user designates double-sided printing, single-sidedprinting is automatically set. In the case of this designatedcombination, the UI section 405 displays, for example, the message “THISPAPER TYPE IS NOT RECOMMENDED FOR DOUBLE-SIDED PRINTING. WHEN PRINTING,SINGLE-SIDED PRINTING IS USED.” as shown in (1) of FIG. 6B and FIG. 6Con the display 209. At this time, a content to be displayed as a messageis not limited thereto. For example, the message “SINGLE-SIDED PRINTINGIS SET.” or the like may be displayed. A message displayed at this timeis displayed when the setting section 406 sets 1 for a double-sidedprinting prohibition flag. For this reason, hereinafter, this message isreferred to as double-sided printing prohibition message.

When the FU tray 116 is closed with the same designated combination, themessage “OPEN FU TRAY 116.” is displayed on the display 209 in additionto the double-sided printing prohibition message, as shown in (2) ofFIG. 6B and FIG. 6D. At this time, a content to be displayed as amessage is not limited thereto. Depending on a user, it is conceivablethat the user does not know that, for example, a paper type, such asthick paper and envelope, is FU output recommended paper or the userdoes not know that the FU tray 116 is an opening/closing member.Accordingly, for example, the message “THIS PAPER TYPE IS FU OUTPUTRECOMMENDED PAPER. OPEN FU TRAY.” may be displayed or a pictureillustrating “OPEN FU TRAY 116” may be shown. The message “FU TRAY 116IS CLOSED.” informing a user of the open/closed state of the FU tray 116itself may be displayed. A message displayed at this time is displayedwhen the setting section 406 sets 1 for an FU tray 116 open flag. Forthis reason, hereinafter, this message is referred to as FU tray 116open message.

When a user designates FU output recommended paper and single-sidedprinting, a sheet is desirably output to the FU tray 116 along theconveying path with a large radius of curvature rather than being outputto the FD tray 115 along the conveying path with a small radius ofcurvature for the above-described reason. At this time, when the FU tray116 is open, no messages is displayed. On the other hand, when the FUtray 116 is closed, the message “OPEN FU TRAY 116.” as shown in (4) ofFIG. 6B and FIG. 6F is displayed on the display 209. This message issimilar to the content of the above-described FU tray 116 open message,so the description is omitted.

Subsequently, the case where a user designates a paper type other thanFU output recommended paper and double-sided printing will be described.At this time, when the FU tray 116 is open, the double-sided printingconveying path disappears, so double-sided printing cannot be performed.Accordingly, when the FU tray 116 is open, the message “CLOSE FU TRAY116.” as shown in (3) of FIG. 6B and FIG. 6E is displayed on the display209. At this time, a content to be displayed as a message is not limitedthereto. For example, the message “FU TRAY 116 IS OPEN.” or the like maybe displayed. A message displayed at this time is displayed when thesetting section 406 sets 1 for an FU tray 116 close flag. For thisreason, hereinafter, this message is referred to as FU tray 116 closemessage.

As described above, the setting section 406 selects and sets a messageaccording to a combination of paper type information, a selected statusof double-sided printing or single-sided printing, and an open/closedstate of the FU tray 116, acquired by the transmission and receptionsection 407. When the UI section 405 displays a set message on thedisplay 209, an operation performed by the printer 212 to perform aprinting operation desired by a user can be informed to the user.

Informing Message according to Combination of Information on ImageFormation, Designated by User

Hereinafter, a process that the CPU 201 informs a message to a useraccording to a combination of information on image formation, designatedby the user, by using the application 404 will be described withreference to the flowcharts shown in FIG. 7A and FIG. 7B.

Initially, when the host computer 200 receives a command to startadvanced settings for printing operation from a user, the processproceeds to S1100. In S1100, when the UI section 405 causes the display209 to display the advanced settings screen for printing operation, theadvanced settings for printing operation start, and the process proceedsto S1101. The advanced settings screen for printing operation is, forexample, the screen shown in FIG. 9A and contains tabs for basicsettings, extended settings, automatic settings, and the like. When thebasic settings tab is selected, settings including, for example, papersize, print orientation, the number of copies, paper type, resolution,double-sided printing or booklet printing or single-sided printing,paper source, and the like are available. On this advanced settingsscreen for printing operation, when a user completes advanced settingsfor printing operation and depresses OK button, the advanced settingsscreen for printing operation closes. In the present embodiment, acombination of a setting of paper type and a setting of double-sidedprinting or single-sided printing in the basic settings tab is used.When a user does not select double-sided printing or single-sidedprinting, a printing operation of 1 (single-sided printing) is selectedas a default setting.

In S1101, when the UI section 405 has acquired information that a papertype of 1 (paper type other than FU output recommended paper) isselected by the user in selecting a paper type on the advanced settingsscreen for printing operation, the process proceeds to S1110. In S1110,when the UI section 405 has acquired information that a printingoperation of 1 (single-sided printing) is selected in selectingdouble-sided printing or single-sided printing on the advanced settingsscreen for printing operation, the process proceeds to S1115. In S1115,the next step depends on whether the UI section 405 has acquiredinformation resulting from the fact that the user has completed theinput of printing operation on the advanced settings screen for printingoperation and depressed OK button.

In S1110, when the UI section 405 has acquired information that aprinting operation of 2 (double-sided printing) is selected by the userin selecting double-sided printing or single-sided printing on theadvanced settings screen for printing operation, the process proceeds toS1111. In S1111, the transmission and reception section 407 acquires theopen/closed state of the FU tray 116 of the printer 212. In S1112, whenthe transmission and reception section 407 has not acquired a detectionresult that “the FU tray 116 is open” as a detection result of the FUtray open/close sensor 117 of the printer 212 (when the FU tray 116 isclosed) (No), the process proceeds to S1114. In S1114, the settingsection 406 sets 0 for the FU tray 116 close flag for displaying themessage prompting to close the FU tray 116 for double-sided printing,and the process proceeds to S1115. In S1115, the UI section 405 waitsuntil the UI section 405 receives information resulting from the factthat the user has completed advanced settings for printing operation onthe advanced settings screen for printing operation and depressed OKbutton. In S1112, when the transmission and reception section 407 hasacquired a detection result that “the FU tray 116 is open” as adetection result of the FU tray open/close sensor 117 of the printer 212(Yes), the process proceeds to S1113. In S1113, the setting section 406sets 1 for the FU tray 116 close flag for displaying the messageprompting to close the FU tray 116 for double-sided printing, and theprocess proceeds to S1115.

In S1101, when the UI section 405 has acquired information that a papertype of 2 (FU output recommended paper) is selected by the user inselecting a paper type on the advanced settings screen for printingoperation, the process proceeds to S1102. In S1102, when the UI section405 has acquired information that a printing operation of 1(single-sided printing) is selected by the user in selectingdouble-sided printing or single-sided printing on the advanced settingsscreen for printing operation, the process proceeds to S1105. In S1105,the setting section 406 sets 0 for the double-sided printing prohibitionflag for displaying that double-sided printing is prohibited, and theprocess proceeds to S1106.

In S1106, the transmission and reception section 407 acquires theopen/closed state of the FU tray 116 of the printer 212. In S1107, whenthe transmission and reception section 407 has acquired a detectionresult that “the FU tray 116 is open” as a detection result of the FUtray open/close sensor 117 of the printer 212 (Yes), the processproceeds to S1108. In S1108, the setting section 406 sets 0 for the FUtray 116 open flag for displaying the message prompting to open the FUtray 116, and the process proceeds to S1115. In S1107, when thetransmission and reception section 407 has not acquired a detectionresult that “the FU tray 116 is open” as a detection result of the FUtray open/close sensor 117 of the printer 212 (when the FU tray 116 isclosed) (No), the process proceeds to S1109. In S1109, the settingsection 406 sets 1 for the FU tray 116 open flag for displaying themessage prompting to open the FU tray 116, and the process proceeds toS1115.

In S1102, when the UI section 405 has acquired information that aprinting operation of 2 (double-sided printing) is selected by the userin selecting double-sided printing or single-sided printing on theadvanced settings screen for printing operation, the process proceeds toS1103. In S1103, the setting section 406 sets 1 for the double-sidedprinting prohibition flag for displaying that double-sided printing isprohibited, and the process proceeds to S1104. In S1104, the settingsection 406 changes the printing operation to a printing operation of 1(single-sided printing), and the process proceeds to S1106. S1106 toS1115 have been described above, so the description is omitted.

In S1115, the next step depends on whether the UI section 405 hasacquired information resulting from the fact that the user has completedthe input of printing operation on the advanced settings screen forprinting operation and depressed OK button. When the UI section 405 hasnot acquired information that the user has completed the input ofprinting operation and depressed OK button (No), the advanced settingsscreen for printing operation remains displayed, and the steps of S1101to S1114 are repeated. Thus, the user is able to continue advancedsettings for printing operation.

When the UI section 405 has acquired information that the user hascompleted the input of printing operation and depressed OK button (Yes),the process proceeds to the next step. In the next step, a processaccording to whether various flags are set by the setting section 406 onthe advanced settings screen for printing operation is performed throughS1116 to S1119.

When the setting section 406 sets 1 for the double-sided printingprohibition flag (S1116) and sets 1 for the FU tray 116 open flag(S1117) on the advanced settings screen for printing operation, the UIsection 405 displays the message (2) in S1120. The message (2) is, forexample, the message shown in (2) of FIG. 6B or in FIG. 6D and shows thecontents of two messages, that is, the above-described double-sidedprinting prohibition message and the FU tray 116 open message.

When the setting section 406 sets 1 for the double-sided printingprohibition flag (S1116) and does not set 1 for the FU tray 116 openflag (S1117) on the advanced settings screen for printing operation, theUI section 405 displays the message (1) in S1121. The message (1) is,for example, the message shown in (1) of FIG. 6B or in FIG. 6C and showsthe content of the above-described double-sided printing prohibitionmessage.

When the setting section 406 does not set 1 for the double-sidedprinting prohibition flag (S1116) and sets 1 for the FU tray 116 closeflag (S1118) on the advanced settings screen for printing operation, theUI section 405 displays the message (3) in S1122. The message (3) is,for example, the message shown in (3) of FIG. 6B or in FIG. 6E and showsthe content of the above-described FU tray 116 close message.

When the setting section 406 does not set 1 for the double-sidedprinting prohibition flag (S1116) or set 1 for the FU tray 116 closeflag (S1118), and sets 1 for the FU tray 116 open flag (S1119) on theadvanced settings screen for printing operation, the UI section 405displays the message (4) in S1123. The message (4) is, for example, themessage shown in (4) of FIG. 6B or in FIG. 6F.

In S1120 to S1123, the UI section 405 displays any one of theabove-described various messages on the display 209 such that, forexample, the advanced settings screen for printing operation, shown inFIG. 9A, is partially covered. Various messages displayed at this timeeach contain OK button as shown in, for example, FIG. 6C to FIG. 6F.

In S1124, the UI section 405 continues displaying any one of the variousmessages on the display 209 until the UI section 405 acquiresinformation that OK button has been depressed by the user. In S1124,when the UI section 405 has acquired information that OK button has beendepressed by the user (Yes), the setting section 406 sets 0 for the flagin S1125. The setting section 406 may set 0 for the flag not only whenthe UI section 405 has acquired information that OK button has beendepressed by the user but also when a certain period of time has elapsedfrom when any one of the various messages is displayed. When the settingsection 406 sets 0 for the flag, the UI section 405 clears the any oneof the various messages, displayed on the display 209. At this time, theUI section 405 clears the any one of the various messages and, at thesame time, clears, for example, the advanced settings screen forprinting operation, shown in FIG. 9A, and the process proceeds to S1126.

When the setting section 406 does not set 1 for the double-sidedprinting prohibition flag (S1116), does not set 1 for the FU tray 116close flag (S1118), and does not set 1 for the FU tray 116 open flag(S1119) on the advanced settings screen for printing operation, theprocess proceeds to S1126. At this time, the UI section 405 does notshow any message on the display 209.

In S1126, the next step depends on whether the UI section 405 hasacquired information that a button to be depressed to perform printinghas been depressed by the user. The process does not proceed to the nextstep until the UI section 405 acquires information that the button to bedepressed to perform printing has been depressed by the user. When theUI section 405 has acquired information that the button to be depressedto perform printing has been depressed by the user (Yes), the processproceeds to S1127. In S1127, the transmission and reception section 407transmits image information to the printer controller 213. For variousmessages from S1120 to S1123, the UI section 405 displays any one of thevarious message on the display 209 before the transmission and receptionsection 407 transmits first image information to the printer controller213.

In the present embodiment, it is assumed that, according to messagesdisplayed by the UI section 405 in S1120 to S1123, the user goes to theprinter 212 and performs operation in accordance with instructions ofthe messages. When, for example, the UI section 405 displays the FU tray116 open message in S1123, it is assumed that the user manually opensthe FU tray 116. In the present embodiment, when a user executes aprinting operation for a specified print job, operation needed isinformed to the user. Therefore, even when the user does not manuallyopen the FU tray 116, but when the UI section 405 acquires in S1124information that OK button has been depressed by the user, the processproceeds to the next step, and finally a printing operation can beexecuted. In this way, in the present embodiment, whether the FU tray116 is opened or closed depends on user convenience.

Here, a possible situation in the case where, although the FU tray 116open message is displayed in S1123, the user does not bring the FU tray116 into the open state and depresses OK button will be described.

Depending on a user, even when, for example, FU output recommended paperis designated by the user, the curling of a sheet resulting fromdouble-sided printing or outputting a sheet to the FD tray 115 may beallowed. When a user installs the image forming apparatus 10 such thatthe side at which the FU tray 116 is disposed is close to a wall, theuser is difficult to open or close the FU tray 116. In this case, ratherthan the user puts the hand into the clearance between the image formingapparatus 10 and the wall to open the FU tray 116, the curling of asheet may be allowed. In this case, even when the UI section 405displays the FU tray 116 open message, a user may depress OK buttonwithout any operation on the printer 212. In this case, since the FUtray 116 is left closed, space saving is achieved.

In the present embodiment, after the UI section 405 has acquiredinformation resulting from the fact that the user has completed theinput of printing operation on the advanced settings screen for printingoperation and depressed OK button, any one of various messages isdisplayed. However, such a process that S1115 is placed between S1126and S1125 and the process returns to S1100 when S1124 is negative isapplicable. With this process, each time a user changes settings ofprinting operation on the advanced settings screen for printingoperation, the setting section 406 is able to set an applicable message,and the UI section 405 is able to display the message on the display209.

In the present embodiment, when the UI section 405 acquires informationresulting from the fact that a user has made input for printingoperation on the advanced settings screen for printing operation, theCPU 201 acquires the open/closed state of the FU tray 116.Alternatively, such a process that S1115 is placed between S1100 andS1101 and the process returns to S1100 when S1115 is negative and theprocess returns to S1100 when S1124 is negative is applicable. With thisprocess, the UI section 405 acquires information resulting from the factthat a user has completed input for printing operation and depressed OKbutton on the advanced settings screen for printing operation, and thenthe CPU 201 acquires the open/closed state or the FU tray 116. After theCPU 201 acquires the open/closed state of the FU tray 116, the settingsection 406 is able to set an applicable message, and the UI section 405is able to display the message on the display 209.

When the UI section 405 has acquired information that a paper type of 2is selected by a user in selecting a paper type on the advanced settingsscreen for printing operation in the present embodiment, the UI section405 displays, for example, the message shown in FIG. 9B on the display209. The UI section 405, for example, changes the paper source to the MPtray 140 and displays a message prompting to manually feed a sheet. Whenthe UI section 405 acquires information that OK button contained in themessage has been depressed by a user, the UI section 405 clears themessage. When the message is cleared, the user is able to continueadvanced settings for printing operation, including, for example,double-sided printing or single-sided printing and the like.

Summary of First Embodiment

As described above, in the present embodiment, the UI section 405displays a message on the display 209 according to a combination ofpaper type information, a selected status of double-sided printing orsingle-sided printing, and an open/closed state of the FU tray 116,acquired by the transmission and reception section 407. Thus, a messageis provided only when user's operation is needed according to theopen/closed state of the FU tray 116, so usability improves. A userperforms necessary operation to the printer 212 according to acombination of a print job, so it is possible to reduce the curling ofFU output recommended paper or an inability to perform double-sidedprinting.

Second Embodiment

In the first embodiment, whether a user opens or closes the FU tray 116in accordance with a message displayed by the UI section 405 depends onuser convenience. In addition, the case where the process proceeds tothe next step when a user depresses OK button in a message has beendescribed. In the present embodiment, the case where the process doesnot proceed to the next step until the CPU 201 detects the open/closeoperation of the FU tray 116 according to a message displayed by the UIsection 405 will be described. Thus, it is possible to reduce thecurling of FU output recommended paper or an inability to performdouble-sided printing.

Hereinafter, a process that the CPU 201 informs a message to a useraccording to a combination of information on image formation, input bythe user, by using the application 404 will be described with referenceto the flowcharts shown in FIG. 8A and FIG. 8B. Like step numbers areassigned to the same components as those of the above-describedembodiment, and the description thereof is omitted. The image formingprocess and the hardware configuration are also the same as those of thefirst embodiment, so the description thereof is omitted. In the presentembodiment, each time a user changes a designated printing operation onthe advanced settings screen for printing operation, the setting section406 sets an applicable message, and the UI section 405 displays themessage on the display 209.

Initially, when the host computer 200 receives a command to startadvanced settings for printing operation from a user, the processproceeds to S1100. In S1100, when the UI section 405 causes the display209 to display the advanced settings screen for printing operation, theadvanced settings for printing operation start, and the process proceedsto S1101.

In S1101, when the UI section 405 has acquired information that a papertype of 1 (paper type other than FU output recommended paper) isselected by the user in selecting a paper type on the advanced settingsscreen for printing operation, the process proceeds to S1110. In S1110,when a printing operation of 1 (single-sided printing) is selected inselecting double-sided printing or single-sided printing on the advancedsettings screen for printing operation, the process proceeds to S1115.In S1115, the next step depends on whether the UI section 405 hasacquired information resulting from the fact that the user has completedthe input of printing operation on the advanced settings screen forprinting operation and depressed OK button.

In S1110, when the UI section 405 has acquired information that aprinting operation of 2 (double-sided printing) is selected by the userin selecting double-sided printing or single-sided printing on theadvanced settings screen for printing operation, the process proceeds toS1111. In S1111, the transmission and reception section 407 acquires theopen/closed state of the FU tray 116 of the printer 212. In S1112, whenthe transmission and reception section 407 has not acquired a detectionresult that “the FU tray 116 is open” as a detection result of the FUtray open/close sensor 117 of the printer 212 (when the FU tray 116 isclosed) (No), the process proceeds to S1206. In S1206, the settingsection 406 sets 0 for the FU tray 116 close flag for displaying themessage prompting to close the FU tray 116 for double-sided printing,and the process proceeds to S1115. In S1115, the UI section 405 waitsuntil the UI section 405 receives information resulting from the factthat the user has completed advanced settings for printing operation onthe advanced settings screen for printing operation and depressed OKbutton. In S1112, when the transmission and reception section 407 hasacquired a detection result that “the FU tray 116 is open” as adetection result of the FU tray open/close sensor 117 of the printer 212(Yes), the process proceeds to S1205.

In S1205, the setting section 406 sets 1 for the FU tray 116 close flagfor displaying the message prompting to close the FU tray 116 fordouble-sided printing, the UI section 405 displays the FU tray 116 closemessage on the display 209, and the process returns to S1111. In S1111,the transmission and reception section 407 acquires the open/closedstate of the FU tray 116 of the printer 212. At this time, S1111, S1112,and S1205 are repeated until the transmission and reception section 407acquires a detection result that “the FU tray 116 is closed” as adetection result of the FU tray open/close sensor 117 of the printer 212in S1112 (until S1112 is negative).

The UI section 405 may also clear the FU tray 116 close message when theUI section 405 has acquired information that OK button has beendepressed by the user or when a certain period of time has elapsed fromwhen the FU tray 116 close message is displayed. At this time, thesetting section 406 does not clear the FU tray 116 close flag. For thisreason, even when the UI section 405 clears a message, OK button on theadvanced settings screen for printing operation or a button to bedepressed by a user to perform printing may be not enabled. A similarconfiguration may be applied for the FU tray 116 open message in thedescription below in the present embodiment.

In S1101, when the UI section 405 has acquired information that a papertype of 2 (FU output recommended paper) is selected by the user inselecting a paper type on the advanced settings screen for printingoperation, the process proceeds to S1102. In S1102, when the UI section405 has acquired information that a printing operation of 1(single-sided printing) is selected by the user in selectingdouble-sided printing or single-sided printing on the advanced settingsscreen for printing operation, the process proceeds to S1105. In S1105,the setting section 406 sets 0 for the double-sided printing prohibitionflag for displaying that double-sided printing is prohibited, and theprocess proceeds to S1106. In S1106, the transmission and receptionsection 407 acquires the open/closed state of the FU tray 116 of theprinter 212. In S1107, when the transmission and reception section 407has acquired a detection result that “the FU tray 116 is open” as adetection result of the FU tray open/close sensor 117 of the printer 212(Yes), the process proceeds to S1203. In S1203, the setting section 406sets 0 for the FU tray 116 open flag for displaying the messageprompting to open the FU tray 116, and the process proceeds to S1115. InS1107, when the transmission and reception section 407 has not acquireda detection result that “the FU tray 116 is open” as a detection resultof the FU tray open/close sensor 117 of the printer 212 (when the FUtray 116 is closed) (No), the process proceeds to S1204. In S1204, thesetting section 406 sets 1 for the FU tray 116 open flag for displayingthe message prompting to open the FU tray 116, the UI section 405displays the FU tray 116 open message on the display 209, and theprocess returns to S1106. In S1106, the transmission and receptionsection 407 acquires the open/closed state of the FU tray 116 of theprinter 212. At this time, the process does not proceed to S1115 untilthe transmission and reception section 407 acquires a detection resultthat “the FU tray 116 is open” as a detection result of the FU trayopen/close sensor 117 of the printer 212 in S1107 (until S1107 isaffirmative).

In S1102, when the UI section 405 has acquired information that aprinting operation of 2 (double-sided printing) is selected by the userin selecting double-sided printing or single-sided printing on theadvanced settings screen for printing operation, the process proceeds toS1200. In S1200, the setting section 406 sets 1 for the double-sidedprinting prohibition flag for displaying that double-sided printing isprohibited, the UI section 405 displays the double-sided printingprohibition message on the display 209, and the process proceeds toS1201. Until the setting section 406 acquires information that OK buttonin the double-sided printing prohibition message has been depressed bythe user in S1201 (while S1201 is negative), the UI section 405continues displaying the double-sided printing prohibition message onthe display 209 in S1200. In S1201, when the setting section 406 hasacquired information that OK button in the double-sided printingprohibition message has been depressed by the user (Yes), the processproceeds to S1202. In S1202, the setting section 406 sets 0 for thedouble-sided printing prohibition flag, and the process proceeds toS1104. In S1104, the setting section 406 changes the printing operationto single-sided printing, and the process proceeds to S1106. S1106 toS1115 have been described above, so the description is omitted.

In S1115, the next step depends on whether the UI section 405 hasacquired information resulting from the fact that the user has completedthe input of printing operation on the advanced settings screen forprinting operation and depressed OK button. In S1115, when the UIsection 405 has not acquired information that the user has completed theinput of printing operation and depressed OK button (No), the processreturns to S1101, and the advanced settings screen for printingoperation remains displayed. Thus, the user is able to continue advancedsettings for printing operation.

In S1115, when the UI section 405 has acquired information that the userhas completed the input of printing operation and depressed OK button(Yes), the process proceeds to S1126. In S1126, the UI section 405closes, for example, the advanced settings screen for printingoperation, shown in FIG. 9A, and the process proceeds to S1127.

In S1126, the next step depends on whether the UI section 405 hasacquired information that the button to be depressed to perform printinghas been depressed by the user. In S1126, the process does not proceedto the next step until the UI section 405 acquires information that thebutton to be depressed to perform printing has been depressed by theuser. In S1126, when the UI section 405 has acquired information thatthe button to be depressed to perform printing has been depressed by theuser (Yes), the process proceeds to S1127. In S1127, the transmissionand reception section 407 transmits image information to the printercontroller 213.

In the present embodiment, it is assumed that, according to messagesdisplayed by the UI section 405, the user goes to the printer 212 andperforms operation in accordance with instructions of the messages.When, for example, the UI section 405 displays the FU tray 116 openmessage in S1204, it is assumed that the user manually opens the FU tray116. In the present embodiment, opening or closing of the FU tray 116may be automatically controlled.

When opening or closing of the FU tray 116 is automatically controlled,the FU tray 116 is automatically opened at point (A) between S1204 andS1106, and the FU tray 116 is automatically closed at point (B) betweenS1205 and S1111.

Here, the drive of the FU tray 116 when the FU tray 116 is automaticallyopened or closed will be described. The image forming apparatus 10includes a driving section at a hinge-side part (not shown) that is usedwhen the FU tray 116 is opened or closed. The driving section includesthe FU tray open/close motor 330 that is a driving source capable ofrotating in forward and reverse directions. A reduction gear train (notshown) that is a drive transmission unit transmits the drive of the FUtray open/close motor 330 to a hinge opening/closing shaft (not shown)and a hinge lift shaft (not shown) to open or close the FU tray 116.

Summary of Second Embodiment

As described above, in the present embodiment, the UI section 405displays a message on the display 209 according to a combination ofpaper type information, a selected status of double-sided printing orsingle-sided printing, and an open/closed state of the FU tray 116,acquired by the transmission and reception section 407. The case wherethe process does not proceed to the next step until the CPU 201 detectsthe open/close operation of the FU tray 116 as a result of the fact thata user performs a necessary operation on the printer 212 in response toa message displayed by the UI section 405 has been described. Thus, itis possible to reduce the curling of FU output recommended paper or aninability to perform double-sided printing. When opening or closing ofthe FU tray 116 is automatically controlled, a user does not need to goto the printer 212 and manually operate the FU tray 116. Therefore, evenwhen the distance between the installation location of the host computer200 and the installation location of the printer 212 is long, it ispossible to reduce the curling of FU output recommended paper or aninability to perform double-sided printing.

Third Embodiment

In the first and second embodiments, the CPU 201 uses the application404 to inform a message only when user's operation is needed accordingto a combination of a print job designated by the user and anopen/closed state of the FU tray 116. In addition, the case where a useris able to perform both input of a print job and checking of a messageon the host computer 200 has been described. In the present embodiment,the case where, in the printer controller 213, the CPU 214 displays anyone of various messages as described above on a main body display 145according to information on a print job, received from the host computer200, will be described. The CPU 214 is capable of communicatinginformation with the host computer 200 by using the bidirectionalinterface (interface) 211 via the input section 218 and providesinformation or the like in the printer 212 to the host computer 200.Therefore, a message to be displayed on the main body display 145 mayalso be displayed on the display 209.

Even when the image forming apparatus 10 does not include the main bodydisplay 145, a user is able to check a message on the display 209 of aPC, smartphone, or the like that is the host computer 200.Alternatively, the image forming apparatus 10 may be equipped with adevice that provides a voice, and may inform, for example, the messagecontent shown in FIG. 6B by voice. Alternatively, the image formingapparatus 10 may be equipped with an LED lamp, and may inform, forexample, the message content shown in FIG. 6B by a pattern of lightingor blinking of the lamp, a change in color, and the like.

FIG. 10 is a block diagram showing functions in the case where the CPU214 loads the control program stored in the program ROM of the ROM 216or the external memory (not shown) onto the RAM 215 and executes thecontrol program. The printer controller 213 mainly functions as a UIsection 501 and a setting section 502. The functions of the UI section501 and setting section 502 at this time are the same as the functionsof the UI section 405 and setting section 406. In the presentembodiment, the CPU 302 may execute a process to be executed by the CPU214. At this time, the CPU 302 loads the control program stored in theprogram ROM of the ROM 303 or the external memory (not shown) onto theRAM 304 and executes the control program.

Hereinafter, a process that the CPU 214 executes at the time ofinforming a message to a user according to a combination of a print job,received from the host computer 200, will be described with reference tothe flowcharts shown in FIG. 11A and FIG. 11B. Like step numbers areassigned to the same steps as those of the above-described embodiments,and the description thereof is omitted. The image forming process andthe hardware configuration are also the same as those of theabove-described embodiments, so the description thereof is omitted.

In S1300, when the printer controller 213 receives information on aprint job from the host computer 200, the process proceeds to S1301. InS1301, when the UI section 501 has acquired information that a papertype of 1 (paper type other than FU output recommended paper) isselected by the user in selecting a paper type on the advanced settingsscreen for printing operation, the process proceeds to S1310. In S1310,when the UI section 501 has acquired information that a printingoperation of 1 (single-sided printing) is selected in selectingdouble-sided printing or single-sided printing on the advanced settingsscreen for printing operation, the process proceeds to S1315 and thefollowing steps.

In S1310, when the UI section 501 has acquired information that aprinting operation of 2 (double-sided printing) is selected by the userin selecting double-sided printing or single-sided printing on theadvanced settings screen for printing operation, the process proceeds toS1311. In S1311, the CPU 214 acquires the open/closed state of the FUtray 116 of the printer 212. In S1312, when the CPU 214 has not acquireda detection result that “the FU tray 116 is open” as a detection resultof the FU tray open/close sensor 117 of the printer 212 (when the FUtray 116 is closed) (No), the process proceeds to S1314. In S1314, thesetting section 502 sets 0 for the FU tray 116 close flag for displayingthe message prompting to close the FU tray 116 for double-sidedprinting, and the process proceeds to S1315 and the following steps. InS1312, when the CPU 214 has acquired a detection result that “the FUtray 116 is open” as a detection result of the FU tray open/close sensor117 of the printer 212 (Yes), the process proceeds to S1313. In S1313,the setting section 502 sets 1 for the FU tray 116 close flag fordisplaying the message prompting to close the FU tray 116 fordouble-sided printing, and the process proceeds to S1315 and thefollowing steps.

In S1301, when the UI section 501 has acquired information that a papertype of 2 (FU output recommended paper) is selected by the user inselecting a paper type on the advanced settings screen for printingoperation, the process proceeds to S1302. In S1302, when the UI section501 has acquired information that a printing operation of 1(single-sided printing) is selected by the user in selectingdouble-sided printing or single-sided printing on the advanced settingsscreen for printing operation, the process proceeds to S1304. In S1304,the setting section 502 sets 0 for the double-sided printing prohibitionflag for displaying that double-sided printing is prohibited, and theprocess proceeds to S1306.

In S1306, the CPU 214 acquires the open/closed state of the FU tray 116of the printer 212. In S1307, when the CPU 214 has acquired a detectionresult that “the FU tray 116 is open” as a detection result of the FUtray open/close sensor 117 of the printer 212 (Yes), the processproceeds to S1308. In S1308, the setting section 502 sets 0 for the FUtray 116 open flag for displaying the message prompting to open the FUtray 116, and the process proceeds to S1315 and the following steps. InS1307, when the CPU 214 has not acquired a detection result that “the FUtray 116 is open” as a detection result of the FU tray open/close sensor117 of the printer 212 (when the FU tray 116 is closed) (No), theprocess proceeds to S1309. In S1309, the setting section 502 sets 1 forthe FU tray 116 open flag for displaying the message prompting to openthe FU tray 116, and the process proceeds to S1315.

In S1302, when the UI section 501 has acquired information that aprinting operation of 2 (double-sided printing) is selected by the userin selecting double-sided printing or single-sided printing on theadvanced settings screen for printing operation, the process proceeds toS1303. In S1303, the setting section 502 sets 1 for the double-sidedprinting prohibition flag for displaying that double-sided printing isprohibited, and the process proceeds to S1305. In S1305, the settingsection 502 changes the printing operation to a printing operation of 1(single-sided printing), and the process proceeds to S1306. S1306 toS1309 have been described above, so the description is omitted.

In S1315 and the following steps, the next step depends on whether thesetting section 502 sets a flag.

When the setting section 502 sets 1 for the double-sided printingprohibition flag (S1315) and sets 1 for the FU tray 116 open flag(S1316) on the advanced settings screen for printing operation, the UIsection 501 displays the message (2) in S1319. The message (2) is, forexample, the message shown in (2) of FIG. 6B or in FIG. 6D and shows thecontents of two messages, that is, the above-described double-sidedprinting prohibition message and the FU tray 116 open message.

When the setting section 502 sets 1 for the double-sided printingprohibition flag (S1315) and does not set 1 for the FU tray 116 openflag (S1316) on the advanced settings screen for printing operation, theUI section 501 displays the message (1) in S1320. The message (1) is,for example, the message shown in (1) of FIG. 6B or in FIG. 6C and showsthe content of the above-described double-sided printing prohibitionmessage.

When the setting section 502 does not set 1 for the double-sidedprinting prohibition flag (S1315) and sets 1 for the FU tray 116 closeflag (S1317) on the advanced settings screen for printing operation, theUI section 501 displays the message (3) in S1321. The message (3) is,for example, the message shown in (3) of FIG. 6B or in FIG. 6E and showsthe content of the above-described FU tray 116 close message.

When the setting section 502 does not set 1 for the double-sidedprinting prohibition flag (S1315) or set 1 for the FU tray 116 closeflag (S1317), and sets 1 for the FU tray 116 open flag (S1318) on theadvanced settings screen for printing operation, the UI section 501displays the message (4) in S1322. The message (4) is, for example, themessage shown in (4) of FIG. 6B or in FIG. 6F.

In S1319 to S1321, the UI section 501 displays any one of theabove-described various messages on the main body display 145 or thedisplay 209 or both Various messages displayed at this time each containOK button as shown in, for example, FIG. 6C to FIG. 6F.

In S1323, the UI section 501 continues displaying any one of the variousmessages on at least one of the main body display 145 and the display209 until the UI section 501 acquires information that OK button hasbeen depressed by the user. In S1323, when the UI section 501 hasacquired information that OK button has been depressed by the user(Yes), the setting section 502 sets 0 for the flag in S1324. The settingsection 502 may set 0 for the flag not only when the UI section 501 hasacquired information that OK button has been depressed by the user butalso when a certain period of time has elapsed from when any one of thevarious messages is displayed. When the setting section 502 sets 0 forthe flag, the UI section 501 clears the any one of the various messages,displayed on the at least one of the main body display 145 and thedisplay 209, and the process proceeds to S1325.

When the setting section 502 does not set 1 for the double-sidedprinting prohibition flag (S1315) or set 1 for the FU tray 116 closeflag (S1317) or set 1 for the FU tray 116 open flag (S1318) on theadvanced settings screen for printing operation, the process proceeds toS1325. At this time, the UI section 501 does not show any message on atleast one of the main body display 145 and the display 209.

In S1325, the next step depends on whether the UI section 501 hasacquired information that a button to be depressed to perform printinghas been depressed by the user. The process does not proceed to the nextstep until the UI section 501 acquires information that the button to bedepressed to perform printing has been depressed by the user. When theUI section 501 has acquired information that the button to be depressedto perform printing has been depressed by the user (Yes), the processproceeds to S1326. In S1326, the CPU 214 starts printing.

In the present embodiment, it is assumed that, according to messagesdisplayed by the UI section 501 in S1319 to S1321, the user goes to theprinter 212 and performs operation in accordance with instructions ofthe messages. When, for example, the UI section 501 displays the FU tray116 open message in S1320, it is assumed that the user manually opensthe FU tray 116. In the present embodiment, when a user executes aprinting operation for a specified print job, operation needed isinformed to the user. Therefore, even when the user does not manuallyopen the FU tray 116, but when the UI section 501 acquires in S1323information that OK button has been depressed by the user, the processproceeds to S1326 via S1324 and S1325, and the CPU 214 starts printing.In this way, in the present embodiment, whether the FU tray 116 isopened or closed depends on user convenience.

Here, a possible situation in the case where, although the FU tray 116open message is displayed in S1320, the user does not bring the FU tray116 into the open state and depresses OK button will be described.

Depending on a user, even when, for example, FU output recommended paperis designated by the user, the curling of a sheet resulting fromdouble-sided printing or outputting a sheet to the FD tray 115 may beallowed. When a user installs the image forming apparatus 10 such thatthe side at which the FU tray 116 is disposed is close to a wall, theuser is difficult to open or close the FU tray 116. In this case, ratherthan the user puts the hand into the clearance between the image formingapparatus 10 and the wall to open the FU tray 116, the curling of asheet may be allowed. In this case, even when the UI section 501displays the FU tray 116 open message, a user may depress OK buttonwithout any operation on the printer 212. In this case, since the FUtray 116 is left closed, space saving is achieved.

Summary of Third Embodiment

As described above, in the present embodiment, the CPU 214 controls theprinter 212 according to a combination of paper type informationreceived from the host computer 200, a selected status of double-sidedprinting or single-sided printing, and an open/closed state of the FUtray 116, acquired by the CPU 214. The case where the CPU 214 shows anyone of various messages as described above on at least one of the mainbody display 145 and the display 209 has been described. Thus, a messageis provided only when user's operation is needed according to theopen/closed state of the FU tray 116, so usability improves. A userperforms necessary operation to the printer 212 according to acombination of a print job, so it is possible to reduce the curling ofFU output recommended paper or an inability to perform double-sidedprinting.

Fourth Embodiment

In the third embodiment, the case where whether a user opens or closesthe FU tray 116 in accordance with a message displayed by the UI section501 depends on user convenience and the process proceeds to the nextstep when the user depresses OK button has been described. In thepresent embodiment, the case where the process does not proceed to thenext step until the CPU 214 detects the open/close operation of the FUtray 116 according to a message displayed by the UI section 501 will bedescribed. Thus, it is possible to reduce the curling of FU outputrecommended paper or an inability to perform double-sided printing.

In the printer controller 213, the CPU 214 controls the printer 212 inaccordance with information on a print job, received from the hostcomputer 200. Hereinafter, a process that the CPU 214 executes at thetime of displaying any one of various message as described above on atleast one of the main body display 145 and the display 209 will bedescribed with reference to the flowcharts shown in FIG. 12A and FIG.12B. Like step numbers are assigned to the same steps as those of theabove-described embodiments, and the description thereof is omitted. Theimage forming process and the hardware configuration are also the sameas those of the first embodiment, so the description thereof is omitted.In the present embodiment, the CPU 302 may execute a process to beexecuted by the CPU 214.

In S1300, when the printer controller 213 receives information on aprint job from the host computer 200, the process proceeds to S1301. InS1301, when the UI section 501 has acquired information that a papertype of 1 (paper type other than FU output recommended paper) isselected by the user in selecting a paper type on the advanced settingsscreen for printing operation, the process proceeds to S1310. In S1310,when a printing operation of 1 (single-sided printing) is selected inselecting double-sided printing or single-sided printing on the advancedsettings screen for printing operation, the process proceeds to S1327.In S1327, the CPU 214 starts printing.

In S1310, when the UI section 501 has acquired information that aprinting operation of 2 (double-sided printing) is selected by the userin selecting double-sided printing or single-sided printing on theadvanced settings screen for printing operation, the process proceeds toS1311. In S1311, the CPU 214 acquires the open/closed state of the FUtray 116 of the printer 212. In S1312, when the CPU 214 has not acquireda detection result that “the FU tray 116 is open” as a detection resultof the FU tray open/close sensor 117 of the printer 212 (when the FUtray 116 is closed) (No), the process proceeds to S1407. In S1407, thesetting section 502 sets 0 for the FU tray 116 close flag for displayingthe message prompting to close the FU tray 116 for double-sidedprinting, and the process proceeds to S1327. In S1327, the CPU 214starts printing. In S1312, when the CPU 214 has acquired a detectionresult that “the FU tray 116 is open” as a detection result of the FUtray open/close sensor 117 of the printer 212 (Yes), the processproceeds to S1406.

In S1406, the setting section 502 sets 1 for the FU tray 116 close flagfor displaying the message prompting to close the FU tray 116 fordouble-sided printing. Then, the UI section 501 shows the FU tray 116close message on at least one of the main body display 145 and thedisplay 209, and the process returns to S1311. In S1311, the CPU 214acquires the open/closed state of the FU tray 116 of the printer 212. Atthis time, S1311, S1312, and S1406 are repeated until the CPU 214acquires a detection result that “the FU tray 116 is closed” as adetection result of the FU tray open/close sensor 117 of the printer 212in S1312 (until S1312 is negative).

The UI section 501 may also clear the FU tray 116 close message when theUI section 501 has acquired information that OK button has beendepressed by the user or when a certain period of time has elapsed fromwhen the FU tray 116 close message is displayed. At this time, thesetting section 502 does not clear the FU tray 116 close flag. For thisreason, even when the UI section 501 clears a message, OK button on theadvanced settings screen for printing operation or the button to bedepressed by a user to execute printing may be not enabled. A similarconfiguration may be applied for the FU tray 116 open message in thedescription below in the present embodiment.

In S1301, when the UI section 501 has acquired information that a papertype of 2 (FU output recommended paper) is selected by the user inselecting a paper type on the advanced settings screen for printingoperation, the process proceeds to S1302. In S1302, when the UI section501 has acquired information that a printing operation of 1(single-sided printing) is selected by the user in selectingdouble-sided printing or single-sided printing on the advanced settingsscreen for printing operation, the process proceeds to S1401. In S1401,the setting section 502 sets 0 for the double-sided printing prohibitionflag for displaying that double-sided printing is prohibited, and theprocess proceeds to S1306. In S1306, the CPU 214 acquires theopen/closed state of the FU tray 116 of the printer 212. In S1307, whenthe CPU 214 has acquired a detection result that “the FU tray 116 isopen” as a detection result of the FU tray open/close sensor 117 of theprinter 212 (Yes), the process proceeds to S1404. In S1404, the settingsection 502 sets 0 for the FU tray 116 open flag for displaying themessage prompting to open the FU tray 116, and the process proceeds toS1327. In S1307, when the CPU 214 has not acquired a detection resultthat “the FU tray 116 is open” as a detection result of the FU trayopen/close sensor 117 of the printer 212 (when the FU tray 116 isclosed) (No), the process proceeds to S1405. In S1405, the settingsection 502 sets 1 for the FU tray 116 open flag for displaying themessage prompting to open the FU tray 116. Then, the UI section 501shows the FU tray 116 open message on at least one of the main bodydisplay 145 and the display 209, and the process returns to S1306. InS1306, the CPU 214 acquires the open/closed state of the FU tray 116 ofthe printer 212. At this time, the process does not proceed to S1327until the CPU 214 acquires a detection result that “the FU tray 116 isopen” as a detection result of the FU tray open/close sensor 117 of theprinter 212 in S1307 (until S1307 is affirmative).

In S1302, when the UI section 501 has acquired information that aprinting operation of 2 (double-sided printing) is selected by the userin selecting double-sided printing or single-sided printing on theadvanced settings screen for printing operation, the process proceeds toS1400. In S1400, the setting section 502 sets 1 for the double-sidedprinting prohibition flag for displaying that double-sided printing isprohibited, the UI section 501 displays the double-sided printingprohibition message on at least one of the main body display 145 and thedisplay 209, and the process proceeds to S1402. Until the settingsection 502 acquires information that OK button in the double-sidedprinting prohibition message has been depressed by the user in S1402(while S1402 is negative), the UI section 501 continues displaying thedouble-sided printing prohibition message on the at least one of themain body display 145 and the display 209 in S1400. In S1402, when thesetting section 502 has acquired information that OK button in thedouble-sided printing prohibition message has been depressed by the user(Yes), the process proceeds to S1403. In S1403, the setting section 502sets 0 for the double-sided printing prohibition flag, and the processproceeds to S1305. In S1305, the setting section 502 changes theprinting operation to single-sided printing, and the process proceeds toS1306. S1306 to S1327 have been described above, so the description isomitted.

In the present embodiment, it is assumed that, according to messagesdisplayed by the UI section 501, the user goes to the printer 212 andperforms operation in accordance with instructions of the messages.When, for example, the UI section 501 displays the FU tray 116 openmessage in S1405, it is assumed that the user manually opens the FU tray116. In the present embodiment, opening or closing of the FU tray 116may be automatically controlled.

When opening or closing of the FU tray 116 is automatically controlled,the FU tray 116 is automatically opened at point (C) between S1405 andS1306, and the FU tray 116 is automatically closed at point (D) betweenS1406 and S1311.

Summary of Fourth Embodiment

As described above, in the present embodiment, the CPU 214 controls theprinter 212 according to a combination of paper type informationreceived from the host computer 200, a selected status of double-sidedprinting or single-sided printing, and an open/closed state of the FUtray 116, acquired by the CPU 214. The case where the CPU 214 shows anyone of various messages as described above on at least one of the mainbody display 145 and the display 209 has been described. Thus, a messageis provided only when user's operation is needed according to theopen/closed state of the FU tray 116, so usability improves. A userperforms necessary operation to the printer 212 according to acombination of a print job, so it is possible to reduce the curling ofFU output recommended paper or an inability to perform double-sidedprinting. When opening or closing of the FU tray 116 is automaticallycontrolled, a user does not need to go to the printer 212 and manuallyoperate the FU tray 116. Therefore, even when the distance between theinstallation location of the host computer 200 and the installationlocation of the printer 212 is long, it is possible to execute aprinting operation according to user's intention.

Fifth Embodiment

An image forming apparatus does not always allow input of a sheet outputsection. When a sheet output section is not allowed to be input,information as described in Japanese Patent Laid-Open No. 2015-110455cannot be performed. Even when the sheet output section cannot be input,it is desirable that a sheet be output to the sheet output section towhich a user intends to output the sheet. A recommended sheet outputsection is informed according to a type of sheet input, and a messageprompting to select an intended sheet output section is informed.

Combination of Paper Type Information and Selected Status ofDouble-Sided Printing or Single-Sided Printing, and Message ContentDisplayed

Hereinafter, paper type information, a selected status of double-sidedprinting or single-sided printing, a selected status of sheet outputsection, and a message content displayed on the display 209 of the hostcomputer 200 will be described with reference to FIG. 13A and FIG. 13B.Detailed processes at the time when the setting section 406 actuallyselects and sets a message will be described later.

When a user selects FU output recommended paper, double-sided printingis not performed because of the above-described reason, so, even whenthe user selects double-sided printing, single-sided printing isautomatically set. In the case of this selected combination, the UIsection 405 displays, for example, the message “THIS PAPER TYPE IS NOTRECOMMENDED FOR DOUBLE-SIDED PRINTING. WHEN PRINTING, SINGLE-SIDEDPRINTING IS SET.” as shown in [1] of FIG. 13B and in FIG. 14A on thedisplay 209. At this time, a content to be displayed as a message is notlimited thereto. For example, the message “SINGLE-SIDED PRINTING ISSET.” or the like may be displayed. A message displayed at this time isdisplayed when the setting section 406 sets 1 for a double-sidedprinting prohibition flag. For this reason, hereinafter, this message isreferred to as double-sided printing prohibition message.

When a user selects FU output recommended paper and single-sidedprinting, a sheet may be curled if the sheet is output to the FD tray115 along the conveying path with a small radius of curvature. For thisreason, FU output recommended paper is desirably output to the FU tray116 along the conveying path with a large radius of curvature. Dependingon a user, it is conceivable that the user does not know that, forexample, a paper type, such as thick paper and envelope, is FU outputrecommended paper or the user does not know that the FU tray 116 is anopening/closing member. Accordingly, for example, the message “THISPAPER TYPE IS FU OUTPUT RECOMMENDED PAPER.”, or the like may beinformed.

Depending on a user, even when FU output recommended paper is selectedby the user, the curling of a sheet resulting from outputting paper tothe FD tray 115 may be allowed. When a user installs the image formingapparatus 10 such that the side at which the FU tray 116 is disposed isclose to a wall, the user is difficult to open or close the FU tray 116.In this case, the user may allow the curling of a sheet and may not putthe hand into the clearance between the image forming apparatus 10 andthe wall to open the FU tray 116. In this way, whether to output a sheetto the FD tray 115 or output a sheet to the FU tray 116 depends on userconvenience.

Accordingly, as shown in, for example, [2] of FIG. 13B and in FIG. 14B,information that the paper type selected by a user is FU outputrecommended paper is provided. Alternatively, a message inquiring aboutwhether a user desires to output a sheet to the FD tray 115 or output asheet to the FU tray 116 may be provided to the user. A messagedisplayed at this time is displayed when the setting section 406 sets 1for a sheet output section select flag. For this reason, hereinafter,this message is referred to as sheet output section select message.

When the user selects outputting a sheet to the FU tray 116 in responseto the sheet output section select message, the message “OPEN FU TRAY116.” as shown in, for example, [3] of FIG. 13B and in FIG. 14C may bedisplayed. Alternatively, a picture that makes the user recognize that“open the FU tray 116” may be displayed. A message displayed at thistime is displayed when the setting section 406 sets 1 for an FU tray 116open flag. For this reason, hereinafter, this message is referred to asFU tray 116 open message.

When the user selects outputting a sheet to the FD tray 115 in responseto the sheet output section select message, the message “CLOSE FU TRAY116.” as shown in, for example, [4] of FIG. 13B and in FIG. 14D may bedisplayed. Alternatively, a picture that makes the user recognize that“close the FU tray 116” may be displayed. A message displayed at thistime is displayed when the setting section 406 sets 1 for an FU tray 116close flag. For this reason, hereinafter, this message is referred to asFU tray 116 close message.

Subsequently, the case where a user selects a paper type other than FUoutput recommended paper and double-sided printing will be described.When the FU tray 116 is open, the double-sided printing conveying pathdisappears, so double-sided printing cannot be performed. When the userselects double-sided printing, the message “CLOSE FU TRAY 116.” as shownin, for example, [4] of FIG. 13B and in FIG. 14D may be displayed on thedisplay 209 as described for the FU tray 116 close message. At thistime, a content to be displayed as a message is not limited thereto. Forexample, the message “FU TRAY 116 IS OPEN.” or the like may bedisplayed. A message displayed at this time is displayed when thesetting section 406 sets 1 for an FU tray 116 close flag. For thisreason, hereinafter, this message is referred to as FU tray 116 closemessage.

The sheet output section select message described above may be referredto as first message, and a step in which a first output unit outputs thefirst message may be referred to as first output step. The FU tray 116open message and the FU tray 116 close message may be referred to assecond messages, and a step in which a second output unit outputs thesecond messages may be referred to as second output step. Furthermore,the double-sided printing prohibition message may be referred to asthird message, and a step in which a third output unit outputs the thirdmessage may be referred to as third output step. The UI section 405 mayhave the functions of the first output unit, second output unit, andthird output unit, or different units may respectively have thefunctions of the first output unit, second output unit, and third outputunit.

As described above, the setting section 406 selects and sets a messageaccording to a combination of paper type information, a selected statusof double-sided printing or single-sided printing, and a selected statusof sheet output section. When the UI section 405 displays a set messageon the display 209, an operation performed by the printer 212 to performa printing operation desired by a user can be informed to the user.

Informing Message according to Combination of Information on ImageFormation, Selected by User

Hereinafter, a process that the CPU 201 informs a message to a useraccording to a combination of information on image formation, selectedby the user, by using the application 404 will be described withreference to the flowchart shown in FIG. 15A and FIG. 15B.

Initially, when the host computer 200 receives a command to startadvanced settings for printing operation from a user, the processproceeds to S2100. In S2100, when the UI section 405 causes the display209 to display the advanced settings screen for printing operation, theadvanced settings for printing operation start, and the process proceedsto S2101. The advanced settings screen for printing operation is, forexample, the screen shown in FIG. 9A and contains tabs for basicsettings, extended settings, automatic settings, and the like. When thebasic settings tab is selected, for example, settings including papersize, print orientation, the number of copies, paper type, resolution,double-sided printing or booklet printing or single-sided printing,paper source, and the like are available. On this advanced settingsscreen for printing operation, when a user completes advanced settingsfor printing operation and depresses OK button, the advanced settingsscreen for printing operation closes. In the present embodiment, acombination of a setting of paper type and a setting of double-sidedprinting or single-sided printing in the basic settings tab is used.When a user does not select double-sided printing or single-sidedprinting, single-sided printing is selected as a default setting.

In S2101, when the UI section 405 has acquired information that a papertype other than FU output recommended paper is selected by the user inselecting a paper type, the process proceeds to S2110. In S2110, whenthe UI section 405 has acquired information that single-sided printingis selected in selecting double-sided printing or single-sided printing,the process proceeds to S2112. In S2112, the setting section 406 sets 0for the FU tray 116 close flag for double-sided printing, and theprocess proceeds to S2113. In S2113, the next step depends on whetherthe UI section 405 has acquired information resulting from the fact thatthe user has completed the input of printing operation on the advancedsettings screen for printing operation and depressed OK button.

In S2110, when the UI section 405 has acquired information thatdouble-sided printing is selected by the user in selecting double-sidedprinting or single-sided printing, the process proceeds to S2111. InS2111, the setting section 406 sets 1 for the FU tray 116 close flag fordouble-sided printing, and the process proceeds to S2113.

In S2101, when the UI section 405 has acquired information that FUoutput recommended paper is selected by the user in selecting a papertype, the process proceeds to S2102. In S2102, when the UI section 405has acquired information that single-sided printing is selected by theuser in selecting double-sided printing or single-sided printing, theprocess proceeds to S2104. In S2104, the setting section 406 sets 0 forthe double-sided printing prohibition flag for displaying thatdouble-sided printing is prohibited, and the process proceeds to S2106.

In S2102, when the UI section 405 has acquired information thatdouble-sided printing is selected by the user in selecting double-sidedprinting or single-sided printing, the process proceeds to S2103. InS2103, the setting section 406 sets 1 for the double-sided printingprohibition flag, and the process proceeds to S2105. In S2105, thesetting section 406 changes the printing operation to single-sidedprinting, and the process proceeds to S2106.

In S2106, this is the case where the user subjects FU output recommendedpaper to single-sided printing, and whether to output a sheet to the FDtray 115 or output a sheet to the FU tray 116 depends on userconvenience.

Accordingly, the setting section 406 sets 1 for the sheet output sectionselect flag. The UI section 405 informs that the paper type selected bythe user is FU output recommended paper. Alternatively, the UI section405 displays the sheet output section select message on the display 209as the first message inquiring about whether a user desires to output asheet to the FD tray 115 or output a sheet to the FU tray 116, and theprocess proceeds to S2107.

In S2107, when the UI section 405 has acquired information that FDoutput is selected by the user in selecting a sheet output section, theprocess proceeds to S2108. In S2108, the setting section 406 sets 1 forthe FU tray 116 close flag for FD output of a sheet, and the processproceeds to S2113.

In S2107, when the UI section 405 has acquired information that FUoutput is selected by the user in selecting a sheet output section, theprocess proceeds to S2109. In S2109, the setting section 406 sets 1 forthe FU tray 116 open flag for FU output of a sheet, and the processproceeds to S2113.

In S2113, the next step depends on whether the UI section 405 hasacquired information resulting from the fact that the user has completedthe input of printing operation on the advanced settings screen forprinting operation and depressed OK button. When the UI section 405 hasnot acquired information that the user has completed the input ofprinting operation and depressed OK button (No), the advanced settingsscreen for printing operation remains displayed, and the steps of S2101to S2112 are repeated. Thus, the user is able to continue advancedsettings for printing operation. When the process returns from S2113 toS2101, the setting section 406 sets 0 for the flag that has been set to1 until S2113, and then the process returns to S2101.

When the UI section 405 has acquired information that the user hascompleted the input of printing operation and depressed OK button (Yes),the process proceeds to the next step. In the next step, a processaccording to whether various flags are set by the setting section 406 onthe advanced settings screen for printing operation is performed throughS2114 to S2118.

When the setting section 406 determines in S2114, S2115, and S2116 thatno flag is set to 1 on the advanced settings screen for printingoperation, no message is displayed. Then, for example, the advancedsettings screen for printing operation, shown in FIG. 9A, is cleared,and the process proceeds to S2125.

When the setting section 406 determines in S2114 and S2115 that no flagis set to 1 and determines in S2116 that the flag is set to 1 on theadvanced settings screen for printing operation, the UI section 405displays the message [3] in S2119. The message [3] is, for example, themessage shown in [3] of FIG. 13B or in FIG. 14C, and the content of theabove-described FU tray 116 open message is displayed.

When the setting section 406 determines in S2114 that the flag is notset to 1 and determines in S2115 that the flag is set to 1 on theadvanced settings screen for printing operation, the UI section 405displays the message [4] in S2120. The message [4] is, for example, themessage shown in [4] of FIG. 13B or in FIG. 14D, and the content of theabove-described FU tray 116 close message is displayed.

When the setting section 406 determines in S2114 and S2117 that the flagis set to 1 on the advanced settings screen for printing operation, theUI section 405 displays the message [5] in S2121. The message [5] is,for example, the message shown in [5] of FIG. 13B or in FIG. 14E, andthe contents of two messages, that is, the above-described double-sidedprinting prohibition message and the FU tray 116 open message, aredisplayed.

When the setting section 406 determines in S2114, S2117, and S2118 thatthe flag is set to 1 on the advanced settings screen for printingoperation, the UI section 405 displays the message [6] in S2122. Themessage [6] is, for example, the message shown in [6] of FIG. 13B or inFIG. 14F, and the contents of two messages, that is, the above-describeddouble-sided printing prohibition message and the FU tray 116 closemessage, are displayed.

When the setting section 406 determines in S2114 and S2117 that the flagis set to 1 and determines in S2118 that the flag is not set to 1 on theadvanced settings screen for printing operation, no message isdisplayed. Then, for example, the advanced settings screen for printingoperation, shown in FIG. 9A, is cleared, and the process proceeds toS2125.

In S2119 to S2122, the UI section 405 displays any one of theabove-described various messages on the display 209 such that, forexample, the advanced settings screen for printing operation, shown inFIG. 9A, is partially covered. Various messages displayed at this timecontain OK button as shown in, for example, FIG. 14A to FIG. 14F.

In S2123, the UI section 405 continues displaying any one of the variousmessages on the display 209 until the UI section 405 acquiresinformation that OK button has been depressed by the user. In S2123,when the UI section 405 has acquired information that OK button has beendepressed by the user (Yes), the setting section 406 sets 0 for the flagin S2124. The setting section 406 may set 0 for the flag not only whenthe UI section 405 has acquired information that OK button has beendepressed by the user but also when a certain period of time has elapsedfrom when any one of the various messages is displayed. When the settingsection 406 sets 0 for the flag, the UI section 405 clears the any oneof the various messages, displayed on the display 209. At this time, theUI section 405 clears the any one of the various messages and, at thesame time, clears, for example, the advanced settings screen forprinting operation, shown in FIG. 9A, and the process proceeds to S2125.

In S2125, the next step depends on whether the UI section 405 hasacquired information that a button to be depressed to perform printinghas been depressed by the user. The process does not proceed to the nextstep until the UI section 405 acquires information that the button to bedepressed to perform printing has been depressed by the user. When theUI section 405 has acquired information that the button to be depressedto perform printing has been depressed by the user (Yes), the processproceeds to S2126. In S2126, the transmission and reception section 407transmits image information to the printer controller 213. For variousmessages from S2119 to S2122, the UI section 405 displays any one of thevarious messages on the display 209 before the transmission andreception section 407 transmits first image information to the printercontroller 213.

In the present embodiment, it is assumed that, according to messagesdisplayed by the UI section 405 in S2119 to S2122, the user goes to theprinter 212 and performs operation in accordance with instructions ofthe messages. When, for example, the UI section 405 displays the FU tray116 open message in S2119, it is assumed that the user manually opensthe FU tray 116. In the present embodiment, when a user executes aprinting operation for an input print job, operation needed is informedto the user. Therefore, even when the user does not manually open the FUtray 116, but when the UI section 405 acquires in S2125 information thatOK button has been depressed by the user, the process proceeds to thenext step, and finally a printing operation can be executed. In thisway, in the present embodiment, whether the FU tray 116 is opened orclosed depends on user convenience.

In the present embodiment, after the UI section 405 has acquiredinformation resulting from the fact that the user has completed theinput of printing operation on the advanced settings screen for printingoperation and depressed OK button, any one of various messages isdisplayed. Alternatively, such a process that S2113 is placed betweenS2124 and S2125 and the process returns to S2101 when S2113 is negativeand the process returns to S2100 when S2125 is negative is applicable.With this process, each time a user changes settings of printingoperation on the advanced settings screen for printing operation, thesetting section 406 is able to set an applicable message, and the UIsection 405 is able to display the message on the display 209.

When the UI section 405 has acquired information that FU outputrecommended paper is selected by a user in selecting a paper type in thepresent embodiment, the UI section 405 displays, for example, themessage shown in FIG. 9B on the display 209. The UI section 405, forexample, changes the paper source to the MP tray 140 and displays amessage prompting to manually feed a sheet. When the UI section 405acquires information that OK button contained in the message has beendepressed by a user, the UI section 405 clears the message. When themessage is cleared, the user is able to continue advanced settings forprinting operation, including, for example, double-sided printing orsingle-sided printing, and the like.

In the present embodiment, it is assumed that, according to messagesdisplayed by the UI section 405, the user goes to the printer 212 andperforms operation in accordance with instructions of the messages.When, for example, the UI section 405 displays the FU tray 116 openmessage in S2119, it is assumed that the user manually opens the FU tray116. In the present embodiment, opening or closing of the FU tray 116may be automatically controlled.

When opening or closing of the FU tray 116 is automatically controlled,the FU tray 116 automatically opens in the period from when the UIsection 405 acquires information that the user has depressed OK buttonin response to the message of S2119 or S2121, to S2125. The FU tray 116automatically closes in the period from when the UI section 405 acquiresinformation that the user has depressed OK button in response to themessage of S2120 or S2122, to S2125. At this time, the button to bedepressed by the user to perform printing cannot be depressed untilautomatic opening or closing of the FU tray 116 completes.

Here, the drive of the FU tray 116 when the FU tray 116 is automaticallyopened or closed will be described. The image forming apparatus 10includes a driving section at a hinge-side part (not shown) that is usedwhen the FU tray 116 is opened or closed. The driving section includesthe FU tray open/close motor 330 that is a driving source capable ofrotating in forward and reverse directions. A reduction gear train (notshown) that is a drive transmission unit transmits the drive of the FUtray open/close motor 330 to a hinge opening/closing shaft (not shown)and a hinge lift shaft (not shown) to open or close the FU tray 116.

Summary of Fifth Embodiment

As described above, in the present embodiment, the UI section 405displays on the display 209 a message for selecting a sheet output trayto which a user intends to output a sheet according to a combination ofpaper type information, a selected status of double-sided printing orsingle-sided printing, and a selected status of sheet output section.Then, the UI section 405 displays a message prompting to performoperation needed for the FU tray 116. Thus, when the user selects FUoutput recommended paper, it is possible to perform printing accordingto user's intention, so usability improves. A user performs necessaryoperation to the printer 212 according to a combination of a print job,so it is possible to reduce the curling of FU output recommended paperor an inability to perform double-sided printing.

Sixth Embodiment

In the fifth embodiment, the case where whether a user opens or closesthe FU tray 116 in accordance with a message displayed by the UI section405 depends on user convenience and the process proceeds to the nextstep when the user depresses OK button has been described. In the fifthembodiment, the case where either of the case where a detection resultof the FU tray open/close sensor 117 is used and the case where adetection result of the FU tray open/close sensor 117 is not used isapplicable has been described. In the present embodiment, the case wherethe process does not proceed to the next step until the open/closeoperation of the FU tray 116 in response to a message displayed by theUI section 405 is detected by using a detection result of the FU trayopen/close sensor 117 will be described. Thus, it is possible to reducea curl remaining in FU output recommended paper or an inability toperform double-sided printing.

Hereinafter, control at the time when the CPU 201 uses the application404 to acquire a detection result of the FU tray open/close sensor 117will be described with reference to the block diagram of FIG. 4B again.

When the application 404 functions as the setting section 406, theapplication 404 selects and sets a message to be displayed on thedisplay 209 according to a combination as will be described later. Thecombination is specifically a combination of a paper type selected by auser and a selected status of double-sided printing or single-sidedprinting. A message to be displayed at this time is continuouslydisplayed on the display 209 until an appropriate open/closed state isdetected in accordance with a detection result of the FU tray open/closesensor 117 (hereinafter, also referred to as an open/closed state of theFU tray 116).

When the application 404 functions as the transmission and receptionsection 407, the application 404 communicates between the host computer200 and the printer controller 213. With this communication, thetransmission and reception section 407 functions as an acquisition unitthat acquires a detection result of the FU tray open/close sensor 117.An acquisition step in which the transmission and reception section 407acquires a detection result of the FU tray open/close sensor 117includes a first transmission step of transmitting information forrequesting a detection result and a reception step of receiving thedetection result. Transmission of a print job is performed in a secondtransmission step different from the first transmission step. The secondtransmission step is executed, for example, after a user completesadvanced settings for printing operation and closes the advancedsettings screen for printing operation.

In the present embodiment, after the FU tray 116 open message or the FUtray 116 close message is displayed on the display 209, the open/closedstate of the FU tray 116 is acquired. A message displayed in the casewhere the setting section 406 sets the FU tray 116 open flag or the FUtray 116 close flag again will be described.

When, for example, the FU tray 116 open message shown in [3] of FIG. 13Band in FIG. 14E is displayed, the message “FU TRAY 116 IS CLOSED.”informing a user of the open/closed state of the FU tray 116 itself maybe displayed. When, for example, the FU tray 116 close message shown in[4] of FIG. 13B and in FIG. 14F is displayed, the message “FU TRAY 116IS OPEN.” informing a user of the open/closed state of the FU tray 116itself may be displayed.

Hereinafter, a process that the CPU 201 informs a message to a useraccording to a combination of information on image formation, selectedby a user, by using the application 404 will be described with referenceto the flowchart shown in FIG. 16A and FIG. 16B. Like step numbers areassigned to the same steps as those of the above-described embodiments,and the description thereof is omitted. The image forming process andthe hardware configuration are also the same as those of the fifthembodiment, so the description thereof is omitted. In the presentembodiment, each time a user changes a selected printing operation onthe advanced settings screen for printing operation, the setting section406 sets an applicable message, and the UI section 405 displays themessage on the display 209.

Initially, when the host computer 200 receives a command to startadvanced settings for printing operation from a user, the processproceeds to S2100. In S2100, when the UI section 405 causes the display209 to display the advanced settings screen for printing operation, theadvanced settings for printing operation start, and the process proceedsto S2101.

In S2101, when the UI section 405 has acquired information that a papertype other than FU output recommended paper is selected by the user inselecting a paper type, the process proceeds to S2110. In S2110, whenthe UI section 405 has acquired information that single-sided printingis selected in selecting double-sided printing or single-sided printing,the process proceeds to S2209. In S2209, the setting section 406 sets 0for the FU tray 116 close flag for double-sided printing, and theprocess proceeds to S2113. In S2113, the next step depends on whetherthe UI section 405 has acquired information resulting from the fact thatthe user has completed the input of printing operation on the advancedsettings screen for printing operation and depressed OK button.

In S2110, when the UI section 405 has acquired information thatdouble-sided printing is selected by the user in selecting double-sidedprinting or single-sided printing, the process proceeds to S2210. InS2210, the transmission and reception section 407 acquires theopen/closed state of the FU tray 116 of the printer 212. In S2211, whenthe transmission and reception section 407 has acquired a detectionresult that “the FU tray 116 is open” as a detection result of the FUtray open/close sensor 117 of the printer 212 (Yes), the processproceeds to S2212. In S2212, the setting section 406 sets 1 for the FUtray 116 close flag for double-sided printing, the UI section 405displays the FU tray 116 close message on the display 209, and theprocess returns to S2210. S2210, S2211, and S2212 are repeated until thetransmission and reception section 407 acquires a detection result that“the FU tray 116 is closed” as a detection result of the FU trayopen/close sensor 117 of the printer 212 in S2211 (until S2211 isnegative).

In S2211, when the transmission and reception section 407 has notacquired a detection result that “the FU tray 116 is open” as adetection result of the FU tray open/close sensor 117 of the printer 212(when the FU tray 116 is closed) (No), the process proceeds to S2209. InS2209, the setting section 406 sets 0 for the FU tray 116 close flag fordouble-sided printing, and the process proceeds to S2113.

The UI section 405 may also clear the FU tray 116 close message when theUI section 405 has acquired information that OK button has beendepressed by the user or when a certain period of time has elapsed fromwhen the FU tray 116 close message is displayed. At this time, thesetting section 406 does not clear the FU tray 116 close flag. For thisreason, even when the UI section 405 clears a message, OK button on theadvanced settings screen for printing operation or the button to bedepressed by a user to execute printing may be not enabled. A similarconfiguration may be applied for the FU tray 116 open message in thedescription below in the present embodiment.

In S2101, when the UI section 405 has acquired information that FUoutput recommended paper is selected by the user in selecting a papertype, the process proceeds to S2102. In S2102, when the UI section 405has acquired information that single-sided printing is selected by theuser in selecting double-sided printing or single-sided printing, theprocess proceeds to S2104. In S2104, the setting section 406 sets 0 forthe double-sided printing prohibition flag, and the process proceeds toS2106.

In S2102, when the UI section 405 has acquired information thatdouble-sided printing is selected by the user in selecting double-sidedprinting or single-sided printing, the process proceeds to S2200. InS2200, the setting section 406 sets 1 for the double-sided printingprohibition flag, the UI section 405 displays the double-sided printingprohibition message on the display 209, and the process proceeds toS2201. Until the setting section 406 acquires information that OK buttonin the double-sided printing prohibition message has been depressed bythe user in S2201 (while S2201 is negative), the UI section 405continues displaying the double-sided printing prohibition message onthe display 209 in S2200. In S2201, when the setting section 406 hasacquired information that OK button in the double-sided printingprohibition message has been depressed by the user (Yes), the processproceeds to S2202. In S2202, the setting section 406 sets 0 for thedouble-sided printing prohibition flag, and the process proceeds toS2105. In S2105, the setting section 406 changes the printing operationto single-sided printing, and the process proceeds to S2106.

In S2106, this is the case where the user subjects FU output recommendedpaper to single-sided printing, and whether to output a sheet to the FDtray 115 or output a sheet to the FU tray 116 depends on userconvenience.

Accordingly, the setting section 406 sets 1 for the sheet output sectionselect flag. The UI section 405 informs that the paper type selected bythe user is FU output recommended paper. Furthermore, the UI section 405displays the sheet output section select message on the display 209 asthe first message inquiring about whether a user desires to output asheet to the FD tray 115 or output a sheet to the FU tray 116, and theprocess proceeds to S2107.

In S2107, when the UI section 405 has acquired information that FDoutput is selected by the user in selecting a sheet output section, theprocess proceeds to S2203. In S2203, the transmission and receptionsection 407 acquires the open/closed state of the FU tray 116 of theprinter 212.

In S2204, when the transmission and reception section 407 has acquired adetection result that “the FU tray 116 is open” as a detection result ofthe FU tray open/close sensor 117 of the printer 212 (Yes), the processproceeds to S2205. In S2205, the setting section 406 sets 1 for the FUtray 116 close flag for FD output of a sheet. Then, the UI section 405shows the FU tray 116 close message on the display 209, and the processreturns to S2203. S2203, S2204, and S2205 are repeated until thetransmission and reception section 407 does not acquire a detectionresult that “the FU tray 116 is open” as a detection result of the FUtray open/close sensor 117 of the printer 212 in S2204 (until S2204 isnegative).

In S2204, when the transmission and reception section 407 has notacquired a detection result that “the FU tray 116 is open” as adetection result of the FU tray open/close sensor 117 of the printer 212(when the FU tray 116 is closed) (No), the process proceeds to S2209. InS2209, the setting section 406 sets 0 for the FU tray 116 close flag,and the process proceeds to S2113.

In S2107, when the UI section 405 has acquired information that FUoutput is selected by the user in selecting a sheet output section, theprocess proceeds to S2206. In S2206, the transmission and receptionsection 407 acquires the open/closed state of the FU tray 116 of theprinter 212.

In S2207, when the transmission and reception section 407 has notacquired a detection result that “the FU tray 116 is open” as adetection result of the FU tray open/close sensor 117 of the printer 212(No), the process proceeds to S2208. In S2208, the setting section 406sets 1 for the FU tray 116 open flag for FU output of a sheet. Then, theUI section 405 shows the FU tray 116 open message on the display 209,and the process returns to S2206. S2206, S2207, and S2208 are repeateduntil the transmission and reception section 407 acquires a detectionresult that “the FU tray 116 is open” as a detection result of the FUtray open/close sensor 117 of the printer 212 in S2207 (until S2207 isaffirmative).

In S2207, when the transmission and reception section 407 has acquired adetection result that “the FU tray 116 is open” as a detection result ofthe FU tray open/close sensor 117 of the printer 212 (Yes), the processproceeds to S2209. In S2209, the setting section 406 sets 0 for the FUtray 116 close flag, and the process proceeds to S2113.

In S2113, the next step depends on whether the UI section 405 hasacquired information resulting from the fact that the user has completedthe input of printing operation on the advanced settings screen forprinting operation and depressed OK button. In S2113, when the UIsection 405 has not acquired information that the user has completed theinput of printing operation and depressed OK button (No), the advancedsettings screen for printing operation remains displayed, and the stepsfrom S2101 are repeated. Thus, the user is able to continue advancedsettings for printing operation.

In S2113, when the UI section 405 has acquired information that the userhas completed the input of printing operation and depressed OK button(Yes), the process proceeds to S2125. In S2125, the next step depends onwhether the UI section 405 has acquired information that a button to bedepressed to perform printing has been depressed by the user. Theprocess does not proceed to the next step until the UI section 405acquires information that the button to be depressed to perform printinghas been depressed by the user. When the UI section 405 has acquiredinformation that the button to be depressed to perform printing has beendepressed by the user (Yes), the process proceeds to S2126. In S2126,the transmission and reception section 407 transmits image informationto the printer controller 213. For various messages shown in, forexample, FIG. 14A to FIG. 14F, the UI section 405 displays any one ofthe various messages on the display 209 before the transmission andreception section 407 transmits first image information to the printercontroller 213.

In the present embodiment, it is assumed that, according to messagesdisplayed by the UI section 405, the user goes to the printer 212 andperforms operation in accordance with instructions of the messages.When, for example, the UI section 405 displays the FU tray 116 openmessage in S2206, it is assumed that the user manually opens the FU tray116. In the present embodiment, opening or closing of the FU tray 116may be automatically controlled. When opening or closing of the FU tray116 is automatically controlled, the FU tray 116 automatically closes inS2205 or S2212. The message to be displayed at this time may be notnecessarily, for example, the message shown in [4] of FIG. 13B or inFIG. 14D. The message may be the message “FU TRAY 116 CLOSES”. Whenopening or closing of the FU tray 116 is automatically controlled, theFU tray 116 automatically opens in S2208. The message to be displayed atthis time may be not necessarily, for example, the message shown in [3]of FIG. 13B or in FIG. 14C. The message may be the message “FU TRAY 116OPENS”.

Summary of Sixth Embodiment

As described above, in the present embodiment, the UI section 405displays on the display 209 a message for selecting a sheet output trayto which a user intends to output a sheet according to a combination ofpaper type information, a selected status of double-sided printing orsingle-sided printing, and a selected status of sheet output section.Then, the UI section 405 displays a message prompting to performoperation needed for the FU tray 116. The case where the process doesnot proceed to the next step until the open/close operation of the FUtray 116 is detected as a result of the fact that a user performsnecessary operation on the printer 212 in response to a messagedisplayed by the UI section 405 has been described. Thus, it is possibleto reduce a curl remaining in FU output recommended paper or aninability to perform double-sided printing. When opening or closing ofthe FU tray 116 is automatically controlled, a user does not need to goto the printer 212 and manually operate the FU tray 116. Therefore, evenwhen the distance between the installation location of the host computer200 and the installation location of the printer 212 is long, it ispossible to execute a printing operation according to user's intention.

Seventh Embodiment

In the fifth and sixth embodiments, the CPU 201 uses the application 404to inform a message only when user's operation is needed according to acombination of a print job selected by the user and an open/closed stateof the FU tray 116. In addition, the case where a user is able toperform both input of a print job and checking of a message on the hostcomputer 200 has been described. In the present embodiment, the casewhere, in the printer controller 213, the CPU 214 displays any one ofvarious messages as described above on the main body display 145according to information on a print job, received from the host computer200, will be described. The CPU 214 is capable of communicatinginformation with the host computer 200 by using the bidirectionalinterface (interface) 211 via the input section 218 and providesinformation or the like in the printer 212 to the host computer 200.Therefore, a message to be displayed on the main body display 145 mayalso be displayed on the display 209.

Even when the image forming apparatus 10 does not include the main bodydisplay 145, a user is able to check a message on the display 209 of aPC, smartphone, or the like that is the host computer 200.Alternatively, the image forming apparatus 10 may be equipped with adevice that provides a voice, and may inform, for example, the messagecontent shown in FIG. 13B by voice. Alternatively, the image formingapparatus 10 may be equipped with an LED lamp, and may inform, forexample, the message content shown in FIG. 13B by a pattern of lightingor blinking of the lamp, a change in color, and the like.

FIG. 10 is a block diagram showing functions in the case where the CPU214 loads the control program stored in the program ROM of the ROM 216or the external memory (not shown) onto the RAM 215 and executes thecontrol program. The printer controller 213 mainly functions as a UIsection 501 and a setting section 502. The functions of the UI section501 and setting section 502 at this time are the same as the functionsof the UI section 405 and setting section 406. In the presentembodiment, the CPU 302 may execute a process to be executed by the CPU214. At this time, the CPU 302 loads the control program stored in theprogram ROM of the ROM 303 or the external memory (not shown) onto theRAM 304 and executes the control program.

Hereinafter, a process that the CPU 214 executes at the time ofinforming a message to a user according to a combination of a print job,received from the host computer 200, will be described with reference tothe flowchart shown in FIG. 17A and FIG. 17B. Like step numbers areassigned to the same steps as those of the above-described embodiments,and the description thereof is omitted. The image forming process andthe hardware configuration are also the same as those of theabove-described embodiments, so the description thereof is omitted.

In S2300, when the printer controller 213 receives information on aprint job from the host computer 200, the process proceeds to S2316. InS2316, when the UI section 501 has acquired information that a papertype other than FU output recommended paper is selected by the user inselecting a paper type, the process proceeds to S2320. In S2320, thesetting section 502 sets 0 for the FU tray 116 close flag fordouble-sided printing, and the process proceeds to S2321. In S2321, theCPU 214 starts printing.

In S2316, when the UI section 501 has acquired information thatdouble-sided printing is selected by the user in selecting double-sidedprinting or single-sided printing, the process proceeds to S2317. InS2317, the transmission and reception section 407 acquires theopen/closed state of the FU tray 116 of the printer 212.

In S2318, when the transmission and reception section 407 has acquired adetection result that “the FU tray 116 is open” as a detection result ofthe FU tray open/close sensor 117 of the printer 212 (Yes), the processproceeds to S2319. In S2319, the setting section 502 sets 1 for the FUtray 116 close flag for double-sided printing. Then, the UI section 501shows the FU tray 116 close message on at least one of the main bodydisplay 145 and the display 209, and the process returns to S2317.S2317, S2318, and S2319 are repeated until the transmission andreception section 407 acquires a detection result that “the FU tray 116is closed” as a detection result of the FU tray open/close sensor 117 ofthe printer 212 in S2318 (until S2318 is negative).

In S2318, when the transmission and reception section 407 has notacquired a detection result that “the FU tray 116 is open” as adetection result of the FU tray open/close sensor 117 of the printer 212(when the FU tray 116 is closed) (No), the process proceeds to S2320. InS2320, the setting section 502 sets 0 for the FU tray 116 close flag fordouble-sided printing, and the process proceeds to S2321. In S2321, theCPU 214 starts printing.

The UI section 501 may also clear the FU tray 116 close message when theUI section 501 has acquired information that OK button has beendepressed by the user or when a certain period of time has elapsed fromwhen the FU tray 116 close message is displayed. At this time, thesetting section 502 does not clear the FU tray 116 close flag. For thisreason, even when the UI section 501 clears a message, OK button on theadvanced settings screen for printing operation or the button to bedepressed by a user to execute printing may be not enabled. A similarconfiguration may be applied for the FU tray 116 open message in thedescription below in the present embodiment.

In S2301, when the UI section 501 has acquired information that FUoutput recommended paper is selected by the user in selecting a papertype, the process proceeds to S2302. In S2302, when the UI section 501has acquired information that single-sided printing is selected by theuser in selecting double-sided printing or single-sided printing, theprocess proceeds to S2304. In S2304, the setting section 502 sets 0 forthe double-sided printing prohibition flag, and the process proceeds toS2308.

In S2302, when the UI section 501 has acquired information thatdouble-sided printing is selected by the user in selecting double-sidedprinting or single-sided printing, the process proceeds to S2303. InS2303, the setting section 502 sets 1 for the double-sided printingprohibition flag, the UI section 501 displays the double-sided printingprohibition message on at least one of the main body display 145 and thedisplay 209, and the process proceeds to S2305. Until the settingsection 502 acquires information that OK button in the double-sidedprinting prohibition message has been depressed by the user in S2305(while S2305 is negative), the process returns to S2303. In S2303, theUI section 501 continues displaying the double-sided printingprohibition message on the at least one of the main body display 145 andthe display 209. In S2305, when the setting section 502 has acquiredinformation that OK button in the double-sided printing prohibitionmessage has been depressed by the user (Yes), the process proceeds toS2306. In S2306, the setting section 502 sets 0 for the double-sidedprinting prohibition flag, and the process proceeds to S2307. In S2307,the setting section 502 changes the printing operation to single-sidedprinting, and the process proceeds to S2308.

In S2308, this is the case where the user subjects FU output recommendedpaper to single-sided printing, and whether to output a sheet to the FDtray 115 or output a sheet to the FU tray 116 depends on userconvenience. Accordingly, the setting section 502 sets 1 for the sheetoutput section select flag. The UI section 501 informs that the papertype selected by the user is FU output recommended paper. A sheet outputsection select message inquiring about whether a user desires to outputa sheet to the FD tray 115 or output a sheet to the FU tray 116 isdisplayed on at least one of the main body display 145 and the display209. Then, the process proceeds to S2309.

In S2309, when the UI section 501 has acquired information that FDoutput is selected by the user in selecting a sheet output section, theprocess proceeds to S2310. In S2310, the CPU 214 acquires theopen/closed state of the FU tray 116 of the printer 212.

In S2311, when the CPU 214 has acquired a detection result that “the FUtray 116 is open” as a detection result of the FU tray open/close sensor117 of the printer 212 (Yes), the process proceeds to S2312. In S2312,the setting section 502 sets 1 for the FU tray 116 close flag for FDoutput of a sheet. Then, the UI section 501 shows the FU tray 116 closemessage on at least one of the main body display 145 and the display209, and the process returns to S2310. S2310, S2311, and S2312 arerepeated until the CPU 214 does not acquire a detection result that “theFU tray 116 is open” as a detection result of the FU tray open/closesensor 117 of the printer 212 in S2311 (until S2311 is negative).

In S2311, when the CPU 214 has not acquired a detection result that “theFU tray 116 is open” as a detection result of the FU tray open/closesensor 117 of the printer 212 (when the FU tray 116 is closed) (No), theprocess proceeds to S2320. In S2320, the setting section 502 sets 0 forthe FU tray 116 close flag, and the process proceeds to S2321. In S2321,the CPU 214 starts printing.

In S2309, when the UI section 501 has acquired information that FUoutput is selected by the user in selecting a sheet output section, theprocess proceeds to S2313. In S2313, the CPU 214 acquires theopen/closed state of the FU tray 116 of the printer 212.

In S2314, when the CPU 214 has not acquired a detection result that “theFU tray 116 is open” as a detection result of the FU tray open/closesensor 117 of the printer 212 (No), the process proceeds to S2315. InS2315, the setting section 502 sets 1 for the FU tray 116 open flag forFU output of a sheet. Then, the UI section 501 shows the FU tray 116open message on at least one of the main body display 145 and thedisplay 209, and the process returns to S2313. S2313, S2314, and S2315are repeated until the CPU 214 acquires a detection result that “the FUtray 116 is open” as a detection result of the FU tray open/close sensor117 of the printer 212 in S2314 (until S2314 is affirmative).

In S2314, when the CPU 214 has acquired a detection result that “the FUtray 116 is open” as a detection result of the FU tray open/close sensor117 of the printer 212 (Yes), the process proceeds to S2320. In S2320,the setting section 502 sets 0 for the FU tray 116 close flag, and theprocess proceeds to S2321. In S2321, the CPU 214 starts printing.

In the present embodiment, the UI section 501 displays a messageprompting to perform operation needed for the FU tray 116 as the secondmessage according to a combination of a selected status of sheet outputsection and an open/closed state of the FU tray 116. The FU trayopen/close sensor 117 does not necessarily detect an open/closed stateof the FU tray 116. In accordance with the fact that the UI section 501has acquired in S2309 information that a sheet output section isselected by a user, the setting section 502 may set 1 for the flag fordisplaying the second message, and the UI section 501 may display thesecond message. In this case, the process proceeds to the next step whenthe UI section 501 has acquired information that OK button contained inthe message has been depressed by the user. The setting section 502 mayset 0 for the flag even when the UI section 501 has not acquiredinformation that OK button has been depressed by the user but when acertain period of time has elapsed from when any one of various messagesis displayed. When the setting section 502 sets 0 for the flag, the UIsection 501 clears the any one of the various messages, displayed on thedisplay 209, and the process proceeds to the next step.

In the present embodiment, it is assumed that, according to messagesdisplayed by the UI section 501, the user goes to the printer 212 andperforms operation in accordance with instructions of the messages.When, for example, the UI section 501 displays the FU tray 116 openmessage in S2206, it is assumed that the user manually opens the FU tray116. In the present embodiment, opening or closing of the FU tray 116may be automatically controlled. When opening or closing of the FU tray116 is automatically controlled, the FU tray 116 automatically closes inS2312 or S2319. The message to be displayed at this time may be notnecessarily, for example, the message shown in [4] of FIG. 13B or inFIG. 14D. The message may be the message “FU TRAY 116 CLOSES”. Whenopening or closing of the FU tray 116 is automatically controlled, theFU tray 116 automatically opens in S2315. The message to be displayed atthis time may be not necessarily, for example, the message shown in [3]of FIG. 13B or in FIG. 14C. The message may be the message “FU TRAY 116OPENS”.

Summary of Seventh Embodiment

As described above, in the present embodiment, the case where the CPU214 displays a message on at least one of the main body display 145 andthe display 209 according to information on a print job, received fromthe host computer 200, has been described. Information on a print job atthis time is a combination of paper type information, a selected statusof double-sided printing or single-sided printing, and a selected statusof sheet output section. According to this combination, the UI section501 displays the first message on the at least one of the main bodydisplay 145 and the display 209. The message to be displayed by the UIsection 501 at this time is a message for selecting a sheet output trayto which a user intends to output a sheet. Then, the UI section 501displays a message prompting to perform operation needed for the FU tray116 as the second message according to a combination of a selectedstatus of sheet output section and an open/closed state of the FU tray116.

In the present embodiment, the case where the process does not proceedto the next step until the open/close operation of the FU tray 116 isdetected as a result of the fact that a user performs necessaryoperation on the printer 212 in response to a message displayed by theUI section 501 has been described. Thus, it is possible to reduce a curlremaining in FU output recommended paper or an inability to performdouble-sided printing. When opening or closing of the FU tray 116 isautomatically controlled, a user does not need to go to the printer 212and manually operate the FU tray 116. Therefore, even when the distancebetween the installation location of the host computer 200 and theinstallation location of the printer 212 is long, it is possible toexecute a printing operation according to user's intention.

Eighth Embodiment

When printing operation that forms images on a plurality of sheets andoutputs the sheets to the FD tray is performed, if the FU tray isbrought into the open state before the last sheet of the plurality ofsheets is output to the FD tray, a set of sheets is split into a set onthe FD tray and a set on the FU tray. In addition, the stacking order ofsheets output to the FD tray is reverse to the stacking order of sheetsoutput to the FU tray. For this reason, as, for example, the number ofsheets output to the FU tray increases, sorting the stacking order ofsheets output to the FU tray takes time and effort when sheets output tothe FU tray are brought together into a set of sheets output to the FDtray. For this reason, this may lead to a decrease in usability. Evenwhen the FU tray is brought into the open state before the last sheet ofthe plurality of sheets is output to the FD tray, time and effort tosort the stacking order of sheets is reduced.

Configuration of Image Forming Apparatus

FIG. 18 is a schematic configuration diagram of an image formingapparatus 20 of the present embodiment. Like reference numerals areassigned to the same components to those of the image forming apparatus10 described with reference to FIG. 1 , and the description thereof isomitted.

As described above, components concerned with a series of image formingprocess of forming an image on a sheet are referred to as image formingunit. Components concerned with feeding of a sheet to the image formingunit are referred to as sheet feeding unit. A sheet on which toner isfixed by the image forming unit is conveyed by the set of FU rollers 111that is driven by a DC brushless motor 622 and the pair of FD rollers112 that is driven by a stepping motor 623 and is output to the FD tray115.

The image forming apparatus 20 includes the FD tray 115 to which a sheetis output face down (hereinafter, also referred to as FD output) and theFU tray 116 to which a sheet is output face up (hereinafter, alsoreferred to as FU output). The sheet output conveying path to the FDtray 115 and the sheet output conveying path to the FU tray 116 aredifferent.

The sheet output conveying path to the FD tray 115 is a conveying pathalong which a sheet is conveyed from the set of FU rollers 111, passesthrough the pair of FD rollers 112 and is then stacked on the FD tray115. The sheet output conveying path to the FD tray 115 is also referredto as first sheet output conveying path. When a sheet having an image onits upper surface is conveyed along the first sheet output conveyingpath, the sheet is FD output to the FD tray 115 such that the imagesurface faces downward (face down) (FD). An FD tray sheet output sensor125 is capable of recording the number of sheets output to the FD tray115. The FD tray 115 is also referred to as first sheet output section.

The FU tray 116 is an opening/closing member capable of being switchedbetween an open position and a close position. When the FU tray 116 isin the close position, the FU tray 116 serves as a guiding portion thatguides a sheet to the FD tray 115. When the FU tray 116 is in the openposition, the FU tray 116 serves as not a guiding portion that guides asheet to the FD tray 115 but a sheet output tray capable of carryingsheets.

The sheet output conveying path to the FU tray 116 is a conveying pathalong which a sheet is conveyed from the set of FU rollers 111 and isstacked on the FU tray 116. The sheet output conveying path to the FUtray 116 is also referred to as second sheet output conveying path. Whena sheet having an image on its upper surface is conveyed along thesecond sheet output conveying path, the sheet is FU output to the FUtray 116 such that the image surface faces upward (face up) (FU). The FUtray 116 is also referred to as second sheet output section.

The FU tray open/close sensor 117 is an open/close signal output unitthat outputs a first signal in the closed state of the FU tray 116 andthat outputs a second signal in the open state. A CPU 601 detects theopen/closed state in accordance with the first signal or second signaloutput from the FU tray open/close sensor 117. In other words, the FUtray open/close sensor 117 functions as a detection unit that detectswhether the FU tray 116 is in the open state or in the closed state. Thedetailed function will be described later.

When sheets are fed from the MP tray 140, the CPU 601 rotates the MPsheet feeding roller 142 by driving an MP sheet feeding solenoid 621 viaan I/O port 606. The MP sheet feeding roller 142 feeds sheets stacked onthe MP tray 140 to the pair of MP separation rollers 143. The pair of MPseparation rollers 143 separates one of the conveyed sheets fed by theMP sheet feeding roller 142 and conveys the sheet to the pair ofconveying rollers 105. The sheet fed to the pair of conveying rollers105 is conveyed to the photosensitive drum 122. After the sheet isconveyed to the photosensitive drum 122, a toner image is formed andfixed onto the sheet as in the case of a sheet fed from the sheetfeeding cassette 100 and is output to the FU tray 116 or the FD tray115.

The presence or absence of sheets stacked on the MP tray 140 is detectedby an MP paper presence sensor 141. Sheets stacked on the MP tray 140are fed to an image forming section 120 through a sheet feed conveyingpath along which a sheet is conveyed to the pair of conveying rollers105 such that the upper surface of the sheet in a stacked state facesupward. The sheet feed conveying path at the time when a sheet is fedfrom the MP tray 140 is also referred to as second sheet feed conveyingpath.

When sheets are fed from an optional sheet feeding cassette 2000 aswell, an optional sheet feeding roller 2020 feeds sheets to a pair ofoptional separation rollers 2030. When sheets are fed from an optionalsheet feeding cassette 3000 as well, an optional sheet feeding roller3020 feeds sheets to a pair of optional separation rollers 3030. At thistime, as in the case of the sheet feeding cassette 100 and the MP tray140, the presence or absence of sheets stacked on the optional sheetfeeding cassette 2000 is detected by a sheet detecting sensor 2010, andthe presence or absence of sheets stacked on the optional sheet feedingcassette 3000 is detected by a sheet detecting sensor 3010. The pair ofoptional separation rollers 2030 separates one of the conveyed sheetsand conveys the sheet to a pair of optional conveying rollers 2040. Thepair of optional separation rollers 3030 separates one of the conveyedsheets and conveys the sheet to a pair of optional conveying rollers3040. The sheet fed to the pair of optional conveying rollers 2040 isconveyed to the image forming section 120. The sheet fed to the pair ofoptional conveying rollers 3040 is also conveyed to the image formingsection 120. An operation after a sheet is conveyed to the image formingsection 120 is similar to the case where a sheet is conveyed from thesheet feeding cassette 100 or the MP tray 140.

An operation panel 626 is provided at the top of the image formingapparatus 20. The operation panel 626 is made up of a liquid crystalpanel and a keypad. The liquid crystal panel provides information, suchas instruction details to a user, by displaying an image and/or text.The keypad receives instructions from the user. In the presentembodiment, the operation panel 626 is also referred to as messageoutput unit that outputs information for providing a message to a user.

Configuration of Printer Control System

FIG. 19A is a block diagram that illustrates the configuration of awhole printer control system of the present embodiment. Like referencenumerals are assigned to the same components described with reference toFIG. 3A, and the description thereof is omitted.

FIG. 19B is a block diagram showing the configuration of hardwareconcerned with sheet conveyance control as a software functionimplemented by the printing section 221 of the present embodiment. Likereference numerals are assigned to the same components described withreference to FIG. 3B, and the description thereof is omitted.

The CPU 601 communicates with a ROM 603, a RAM 604, the I/O port 606,and a serial communication port 607 via a communication bus 605. The CPU601 controls the printing section 221 by executing a computer programstored in the ROM 603 and the RAM 604. The CPU 601 executes a programstored in the ROM 603, acquires a calculated result during execution,and saves the calculated result in the RAM 604. Alternatively, the CPU601 and an MPU (not shown) including a plurality of processors, such asmulti-cores, may control the printing section 221 with the plurality ofprocessors. Hereinafter, the CPU 601 is also referred to as controlunit.

A storage section in the printing section 221 is made up of one or morememories such as the ROM 603 and the RAM 604 and stores various piecesof information including a computer program for performing variousoperations (described later), communication parameters for wirelesscommunication, and the like. The storage section in the presentembodiment may be a memory, such as the ROM 603 and the RAM 604. Thestorage section in the present embodiment may be, for example, a storagemedium, such as a flexible disk, a hard disk drive, an optical disk, amagneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatilememory card, and a DVD.

The MP paper presence sensor 141 is controlled by the CPU 601 via an MPpaper presence sensor input circuit 610 and the I/O port 606.

The drive of the MP sheet feeding solenoid 621 is controlled by the CPU601 via an MP sheet feeding solenoid driving circuit 611 and the I/Oport 606. When the MP sheet feeding solenoid 621 is driven for apredetermined time, the MP sheet feeding roller 142 rotates. When the MPsheet feeding roller 142 rotates, sheets stacked on the MP tray 140 areconveyed to the pair of MP separation rollers 143.

The drive of the DC brushless motor 622 is controlled by the CPU 601 viaa DC brushless motor driving circuit 612 and the I/O port 606. The DCbrushless motor 622 drives the set of FU rollers 111.

The drive of the stepping motor 623 is controlled by the CPU 601 via astepping motor driving circuit 613 and the I/O port 606. The steppingmotor 623 drives the pair of FD rollers 112.

The drive of an FU tray open/close sensor 117 is controlled by the CPU601 via an FU tray open/close sensor input circuit 614 and the I/O port606.

The drive of a sheet feeding cassette solenoid 625 is controlled by theCPU 601 via a sheet feeding cassette solenoid driving circuit 616 andthe I/O port 606. When the sheet feeding cassette solenoid 625 is drivenfor a predetermined time, the sheet feeding roller 102 rotates. When thesheet feeding roller 102 rotates, sheets stacked in the sheet feedingcassette 100 are conveyed to the pair of separation rollers 103.

The drive of the registration sensor 106 is controlled by the CPU 601via a registration sensor input circuit 615 and the I/O port 606.

The operation of the after-fixing paper presence sensor 110 iscontrolled by the CPU 601 via an after-fixing paper presence sensorinput circuit 617 and the I/O port 606.

The operation of a double-sided printing conveying sensor 113 iscontrolled by the CPU 601 via a double-sided printing conveying sensorinput circuit 618 and the I/O port 606.

The drive of an FU tray solenoid 144 is controlled by the CPU 601 via anFU tray solenoid driving circuit 619 and the I/O port 606.

The serial communication port 607 is connected to an operation panelcontrol circuit 620. The operation panel 626 is controlled by the CPU601 via the operation panel control circuit 620. The CPU 601 acquiresinformation input by a user with the liquid crystal panel or keypad ofthe operation panel 626 by controlling the serial communication port607.

Method with which FU Tray Open/Close Sensor 117 Detects Open/ClosedState of FU Tray 116

Hereinafter, a method with which the FU tray open/close sensor 117detects the open/closed state of the FU tray 116 will be described inthe present embodiment. FIG. 20A is a perspective view of the imageforming apparatus 20 in a state where the FU tray 116 is open. FIG. 20Bis a cross-sectional view of the image forming apparatus 20 when viewedin the direction of the arrow shown in FIG. 20A. FIG. 20C is aperspective view of the members of the FU tray open/close sensor 117.

As shown in FIG. 20B and FIG. 20C, the FU tray open/close sensor 117 ismade up of a supporting member 30100, a cam member 30200, a flag member30300, and a photo-interrupter 30400 (these are not shown in FIG. 18 ).The photo-interrupter 30400 is an example of an optical sensor used as adetecting section and is capable of outputting a different signaldepending on whether light is interrupted by the flag member 30300.

The supporting member 30100 is attached to the FU tray 116. Thesupporting member 30100 pivots together with the FU tray 116 when the FUtray 116 pivots into the open position. The supporting member 30100supports the cam member 30200.

The cam member 30200 converts the pivot motion of the supporting member30100 to the up and down motion of the flag member 30300.

The flag member 30300 interrupts sensor light from a light emittingportion 30400 a of the photo-interrupter 30400 when the FU tray 116 isin the close position. When the FU tray 116 is in the open position, theflag member 30300 is pushed upward by the cam member 30200, and sensorlight from the light emitting portion 30400 a is received by a lightreceiving portion 30400 b. Arrangement of the light emitting portion30400 a and the light receiving portion 30400 b may be interchanged.

The photo-interrupter 30400 outputs a different signal by switchingbetween two light receiving states, that is, a state where sensor lightfrom the light emitting portion 30400 a is received by the lightreceiving portion 30400 b and a state where the sensor light isinterrupted by the flag member 30300 and is not received. In otherwords, when the FU tray 116 is closed, the photo-interrupter 30400 is ina state where sensor light from the light emitting portion 30400 a isinterrupted by the flag member 30300 and is not received by the lightreceiving portion 30400 b. When the FU tray 116 is open, thephoto-interrupter 30400 is in a state where sensor light from the lightemitting portion 30400 a is not interrupted by the flag member 30300 andis received by the light receiving portion 30400 b.

As described above, when the FU tray 116 is closed, the FU trayopen/close sensor 117 outputs a LOW signal to the CPU 601 via the FUtray open/close sensor input circuit 614 and the I/O port 606. Thesignal is also referred to as first signal. The CPU 601 having receivedthe LOW signal (first signal) detects that the FU tray 116 is in theclosed state.

When the FU tray 116 is open, the FU tray open/close sensor 117 outputsa HIGH signal to the CPU 601 via the FU tray open/close sensor inputcircuit 614 and the I/O port 606. The signal is also referred to assecond signal. The CPU 601 having received the HIGH signal (secondsignal) detects that the FU tray 116 is in the open state.

In this way, the FU tray open/close sensor 117 that outputs the firstsignal in the closed state of the FU tray 116 and that outputs thesecond signal in the open state is also referred to as open/close outputunit.

Operation in Case where FU Tray 116 is Opened During Printing

Hereinafter, the operation in the case where the FU tray 116 is openedwhile performing single-sided printing on each of a plurality of sheetswill be described. Initially, in the closed state of the FU tray 116,the sheet feeding unit feeds sheets to the image forming unit. The imageforming unit forms an image on only one side of each of the plurality ofsheets, and the sheets each having an image only on its one side areoutput to the FD tray 115. When the series of printing operation isperformed, if the FU tray 116 is brought into the open state before thelast sheet of the plurality of sheets is output to the FD tray 115, allthe subsequent pages are output to the FD tray 116. When the order ofpages needs to be considered, a user needs to sort the order of sheetsoutput to the FU tray 116 when the user brings a set of output sheetstogether.

Next, the stacking order of sheets will be described. When sheets areoutput to the FD tray 115, a subsequent sheet is stacked on a previoussheet in a state where the surface of the sheet having an image facesdownward, so the stacking order of sheets is as shown in FIG. 21A. Inother words, when the printing operation ends and the set of sheetsoutput to the FD tray 115 is turned upside down, pages are arranged inascending order. However, when sheets are output to the FU tray 116, asubsequent sheet is stacked on a previous sheet in a state where thesurface of the sheet having an image faces upward, so the stacking orderof sheets is as shown in FIG. 21B. In other words, the set of sheetsoutput to the FU tray 116 when the printing operation ends is in a statewhere pages are arranged in descending order.

When a set of sheets output to the FU tray 116 is brought together intoa set of sheets output to the FD tray 115, operation to change the orderof sheets shown in FIG. 21C is needed. Initially, the set of sheetsoutput to the FU tray 116 is turned upside down into a state where thesurface having an image faces downward. Subsequently, the upside-downset of sheets is stacked onto the set of sheets output to the FD tray115 one by one in order from the top.

In this way, when the order of pages needs to be considered, the orderof sheets output to the FU tray 116 needs to be sorted when a set ofsheets output to the FU tray 116 is brought together into a set ofsheets output to the FD tray 115.

In the present embodiment, even when the FU tray 116 is brought into theopen state before the last sheet of the plurality of sheets is output tothe FD tray 115, time and effort to sort the stacking order of sheets isreduced.

Method of Storing Number of Sheets Fed and Number of Sheets Output

Hereinafter, a method of storing the number of sheets fed and the numberof sheets output will be described. In the present embodiment, one ofsheets stacked in the sheet feeding cassette 100 is picked up by thesheet feeding roller 102 and fed to the pair of conveying rollers 104one by one by the pair of separation rollers 103. In the presentembodiment, the registration sensor 106 detects the leading edge totrailing edge of a sheet conveyed one by one to detect whether the sheethas passed through the registration sensor 106. In the presentembodiment, the registration sensor 106 detects a sheet having passedtherethrough, and the CPU 601 stores the number of sheets passingthrough the registration sensor 106 in the RAM 604. Thus, the number ofsheets fed is counted.

The FD tray sheet output sensor 125 detects the leading edge to trailingedge of a sheet to detect whether the sheet has been output to the FDtray 115. The CPU 601 stores the number of sheets passing through the FDtray sheet output sensor 125 in the RAM 604. Thus, the number of sheetsoutput to the FU tray 116 is counted.

The CPU 601 calculates the number of sheets output to the FU tray 116 bysubtracting the number of sheets output to the FD tray 115, stored inthe RAM 604, from the number of sheets fed, stored in the RAM 604.

When, for example, in a state where five sheets are output to the FDtray 115, the FU tray 116 is opened after the sixth sheet is fed, thesixth sheet having an image is output to the FU tray 116. At this time,the registration sensor 106 detects that the six sheets are fed andstores in the RAM 604 that the six sheets are fed, and the FD tray sheetoutput sensor 125 detects that five sheets are output and stores in theRAM 604 that the five sheets are output. For this reason, the CPU 601calculates the number of sheets output to the FU tray 116 as one.

When the interval between sheets is narrow, in a state where five sheetsare output to the FD tray 115, an image is already formed on the sixthsheet and the seventh sheet may be fed when the FU tray 116 is opened.At this time, after the sixth sheet having an image is output to the FUtray 116, an image is eventually formed on the seventh sheet, and theseventh sheet is output to the FU tray 116. The registration sensor 106detects that the seven sheets are fed and stores in the RAM 604 that theseven sheets are fed, and the FD tray sheet output sensor 125 detectsthat five sheets are output and stores in the RAM 604 that the fivesheets are output. For this reason, the CPU 601 calculates the number ofsheets output to the FU tray 116 as two.

In this way, the CPU 601 calculates the number obtained by subtractingthe number of sheets output to the FD tray 115 from the number of sheetsfed as the number of sheets output to the FU tray 116.

Method of Detecting Sheet in Conveying Path

Hereinafter, a method of detecting a sheet in a conveying path will bedescribed with the registration sensor 106 as an example. As shown inFIG. 20D, the registration sensor 106 is made up of a photo-interrupter31000 and a flag member 31100. The flag member 31100 is freely pivotablyprovided near the photo-interrupter 31000. The photo-interrupter 31000outputs a different signal by switching between two light receivingstates, that is, a state where sensor light from a light emittingportion 31000 a is received by a light receiving portion 31000 b and astate where the sensor light is interrupted by the flag member 31100 andis not received.

When no sheet is present in the conveying path, the flag member 31100 isbrought into contact with the conveying path by its own weight. At thistime, the flag member 31100 is located at a position where the flagmember 31100 does not interrupt sensor light from the light emittingportion 31000 a of the photo-interrupter 31000, and is placed in a statewhere the sensor light is received by the light receiving portion 31000b On the other hand, when a sheet is conveyed to the registration sensor106, the flag member 31100 is brought into contact with the sheet topivot and interrupts sensor light from the light emitting portion 31000a of the photo-interrupter 31000. Arrangement of the light emittingportion 31000 a and the light receiving portion 31000 b may beinterchanged.

As described above, when no sheet is present in the conveying path, theregistration sensor 106 outputs a HIGH signal to the CPU 601 via theregistration sensor input circuit 615 and the I/O port 606. The CPU 601having received the HIGH signal detects that no sheet is present in theconveying path. When a sheet is conveyed to the registration sensor 106,the registration sensor 106 outputs a LOW signal to the CPU 601 via theregistration sensor input circuit 615 and the I/O port 606. The CPU 601having received the LOW signal detects that the sheet is conveyed to theregistration sensor 106. When a sheet is conveyed to the trailing edge,the after-fixing paper presence sensor 110 outputs the HIGH signal tothe CPU 601 after the LOW signal via the after-fixing paper presencesensor input circuit 617 and the I/O port 606.

The CPU 601 detects passage of the leading edge of the sheet as a resultof the fact that the HIGH signal having been received from theafter-fixing paper presence sensor 110 switches to the LOW signal. TheCPU 601 detects passage of the trailing edge of the sheet as a result ofthe fact that the LOW signal having been received from the after-fixingpaper presence sensor 110 switches to the HIGH signal.

The FD tray sheet output sensor 125, the after-fixing paper presencesensor 110, the double-sided printing conveying sensor 113, and the MPpaper presence sensor 141 have similar configurations to that of theregistration sensor 106, so the description is omitted. LOW signalsoutput from these sensors are also referred to as first sheet detectionsignals, and HIGH signals are also referred to as second sheet detectionsignals.

The FD tray sheet output sensor 125 is disposed in the conveying pathbetween the pair of FD rollers 112 and the FD tray 115. The FD traysheet output sensor 125 outputs the first sheet detection signalindicating that a sheet is present or the second sheet detection signalindicating that no sheet is present. When single-sided printing isperformed and the FD tray sheet output sensor 125 outputs the firstsheet detection signal indicating that a sheet is present and thenoutputs the second sheet detection signal indicating that no sheet ispresent, the CPU 601 detects that the sheet is output to the FD tray115. When double-sided printing is performed and the FD tray sheetoutput sensor 125 outputs the first sheet detection signal indicatingthat a sheet is present and then outputs the second sheet detectionsignal indicating that no sheet is present, the CPU 601 detects that therotation of the pair of FD rollers 112 is reversed and the sheet isconveyed in the second conveying direction. When the FD tray 115 isfull, the FD tray sheet output sensor 125 continues outputting the firstsheet detection signal indicating that a sheet is present even after thesheet is output to the FD tray 115. In this case, the CPU 601 detectsthat the FD tray 115 is full and outputs, for example, a message of thecontent “Remove sheets stacked on the FD tray 115” to the operationpanel 626.

The after-fixing paper presence sensor 110 is disposed in the conveyingpath between the image forming unit and the FU roller 111 a and the FUroller 111 b. The after-fixing paper presence sensor 110 outputs thefirst sheet detection signal indicating that a sheet is present or thesecond sheet detection signal indicating that no sheet is present. Theafter-fixing paper presence sensor 110 is also referred to as firstpaper presence sensor.

An after-feeding paper presence sensor 118 is disposed in the conveyingpath between the sheet feeding roller 102 and the pair of conveyingrollers 105. The after-feeding paper presence sensor 118 outputs thefirst sheet detection signal indicating that a sheet is present or thesecond sheet detection signal indicating that no sheet is present. Theafter-feeding paper presence sensor 118 is also referred to as secondpaper presence sensor.

The registration sensor 106 is disposed in the conveying path betweenthe pair of conveying rollers 105 and the image forming unit. Theregistration sensor 106 outputs the first sheet detection signalindicating that a sheet is present or the second sheet detection signalindicating that no sheet is present. The registration sensor 106 is alsoreferred to as third paper presence sensor.

Process in Case where FU Tray 116 is Opened During Printing

Next, in the present embodiment, a specific process that is executed bythe CPU 601 will be described with reference to the flowchart of FIG. 22. In the present embodiment, a series of printing operation in which thesheet feeding unit feeds a plurality of sheets to the image formingunit, the image forming unit forms an image on only one side of each ofthe sheets, and the sheets each having an image only on its one side areoutput to the first sheet output section will be described.

When, before the last sheet of a plurality of sheets is output to the FDtray 115, the FU tray open/close sensor 117 detects that the FU tray 116is in the open state, the CPU 601 cancels feeding of a new sheet andsuspends printing operation. Subsequently, the message output unitprompts a user to remove sheets output to the FU tray 116 and switch theFU tray 116 into the close position. When the FU tray open/close sensor117 detects that the FU tray 116 is in the closed state, the imageforming unit forms an image again subsequent to the image formed on thelast sheet output to the FD tray 115 before the printing operation issuspended. This printing operation is referred to as reprint.

In S3400, the CPU 601 starts a printing operation to output a sheet tothe FD tray 115 in the closed state of the FU tray 116, and the processproceeds to S3401.

In S3401, the next step depends on whether the last sheet of theplurality of sheets is output to the FD tray 115. In S3401, when thelast sheet of the plurality of sheets is output to the FD tray 115(YES), the flowchart ends. In S3401, when the last sheet of theplurality of sheets is not output to the FD tray 115 (NO), the processproceeds to S3402.

In S3402, the FU tray open/close sensor 117 detects the open/closedstate of the FU tray 116. The process returns to S3401 until the FU trayopen/close sensor 117 detects that the FU tray 116 is open (until the FUtray 116 is opened). In S3402, when the FU tray open/close sensor 117detects that the FU tray 116 is open before the last sheet of theplurality of sheets is output to the FD tray 115, the process proceedsto S3403.

In S3403, the CPU 601 cancels feeding of a new sheet with the sheetfeeding roller 102 when there is a subsequent page after the FU trayopen/close sensor 117 detects that the FU tray 116 is in the open state,and the process proceeds to S3404. When there is no subsequent page, thesheet feeding unit has completed feeding all the sheets, so the processproceeds to S3404. The CPU 601 is capable of reducing the number ofsheets to be output to the FU tray 116 that is not an intended outputdestination by cancelling feeding of a new sheet. The CPU 601 is capableof reducing the number of sheets needed to sort the stacking order ofsheets when the sheets are brought together into one set by cancellingfeeding of a new sheet.

In S3404, the CPU 601 detects whether a sheet is present in theconveying path from when the sheet is fed to when the sheet is output tothe FU tray 116. A sheet present in a sheet conveying path from thesheet feeding roller 102 via the pair of conveying rollers 105, thetransfer roller 107, and the fixing device 130 to the set of FU rollers111 is detected by using, for example, the registration sensor 106 orthe after-fixing paper presence sensor 110. In S3404, when a sheet isdetected by, for example, the registration sensor 106 or theafter-fixing paper presence sensor 110, the CPU 601 waits until thedetected sheet is output to the FU tray 116. In other words, initially,the FU tray 116 is opened, and the FU tray open/close sensor 117 detectsthat the FU tray 116 is in the open state. When there is any sheetalready fed by the sheet feeding roller 102 and not output to the FDtray 115 before this timing, the CPU 601 causes the image forming unitto form an image and output the sheet to the FU tray 116. At this time,the number of sheets output to the FU tray 116 is calculated bysubtracting the number of sheets output to the FD tray 115 from thenumber of sheets fed.

In S3405, the CPU 601 suspends the printing operation by stopping allthe motors concerned with conveyance of sheets and stopping imageformation.

In S3406, the CPU 601 displays a message (a) on the operation panel 626.The content of the message displayed on the operation panel 626 at thistime is, for example, the message shown in FIG. 23A. The message (a) isa message prompting a user to “remove sheets output to the FU tray 116and switch the FU tray 116 into the close position”. The message (a)also contains OK button.

In S3407, when the CPU 601 has acquired information that OK button hasbeen depressed by the user, the process proceeds to the next step.

In S3408, the CPU 601 displays a message (b) on the operation panel 626.The content of the message displayed on the operation panel 626 at thistime is, for example, the message shown in FIG. 23B. The message (b) isa message informing the user that “the sheet output to the FU tray 116is subjected to reprinting” at the time of resuming the printingoperation. The message (b) also contains OK button.

In S3409, when the CPU 601 has acquired information that OK button hasbeen depressed by the user, the CPU 601 clears the message (b), and theprocess proceeds to S3410.

In S3410, when the FU tray open/close sensor 117 detects that the FUtray 116 is closed, the process proceeds to S3411.

In S3411, the CPU 601 outputs operation instructions to a sheetconveying mechanism 511, the fixing device 130, and the image formingsection 120 and resumes the printing operation by using the FD tray 115as the sheet output section. At this time, the CPU 601 performs theprinting operation to form an image again subsequent to the image formedon the last sheet output to the FD tray 115 before the printingoperation is suspended. The number of sheets output to the FD tray 115is the number of sheets passing through the FD tray sheet output sensor125.

Through the above-described control, when the printing operationcompletes, all the sheets involved in the printing operation are stackedon the FD tray 115 in order.

The messages (a), (b) are not necessarily displayed on the operationpanel 626. Alternatively, the contents of the messages (a), (b) may beinformed to a user by voice by means of, for example, a readingfunction. Alternatively, the message contents as shown by the messages(a), (b) may be informed to a user by light emitting patterns of an LEDlamp.

In the present embodiment, the case where a different image is formed onone side of each of a plurality of sheets and the FU tray 116 switchesinto the open position while a sheet is output to the FD tray 115 hasbeen described. However, it is not necessarily the case where adifferent image is formed. Alternatively, it may be the case where thesame image is formed on one side of each of a plurality of sheets.

In addition, in the present embodiment, the case where an image isformed on one side of each of a plurality of sheets has been described.Alternatively, it may be the case where an image is formed on both sidesof each of a plurality of sheets.

Summary of Eighth Embodiment

As described above, in the present embodiment, the case where theprinting operation to, in the closed state of the FU tray 116, form animage only on one side of each of a plurality of sheets and output asheet to the FD tray 115 has been described. When, before the last sheetof a plurality of sheets is output to the FD tray 115, the FU trayopen/close sensor 117 detects that the FU tray 116 is in the open state,the CPU 601 cancels feeding of a new sheet and suspends printingoperation. The CPU 601 cancels feeding of a new sheet and suspends theprinting operation. Thus, it is possible to suppress continuous outputof a sheet to the FU tray 116, and it is possible to reduce the numberof sheets to be output to the FU tray 116 that is not an intended outputdestination. Subsequently, the message output unit prompts a user toremove sheets output to the FU tray 116 and switch the FU tray 116 intothe close position. When the FU tray open/close sensor 117 detects thatthe FU tray 116 is closed, the image forming unit forms an image againsubsequent to the image formed on the last sheet output to the FD tray115 before the printing operation is suspended. In other words, reprintis performed. With this operation, a user does not need to change thestacking order of sheets output to the FU tray 116 and restack thesheets onto the FD tray 115, so a set of sheets on the FD tray 115 canbe a set of sheets of which the stacking order is organized.

Ninth Embodiment

In the eighth embodiment, when, before the last sheet of a plurality ofsheets is output to the FD tray 115, the FU tray open/close sensor 117detects that the FU tray 116 is in the open state, the CPU 601 cancelsfeeding of a new sheet. Then, the printing operation is suspended.Subsequently, the message output unit prompts a user to remove sheetsoutput to the FU tray 116 and switch the FU tray 116 into the closeposition. When the FU tray open/close sensor 117 detects that the FUtray 116 is in the closed state, the printing operation in which theimage forming unit forms an image again subsequent to the image formedon the last sheet output to the FD tray 115 before the printingoperation is suspended is performed. In other words, reprint isperformed.

In the present embodiment, the case where a user is prompted to stacksheets output to the FU tray 116 onto a set of sheets stacked on the FDtray 115 to be brought together will be described.

In the present embodiment as well, a series of printing operation inwhich the sheet feeding unit feeds a plurality of sheets to the imageforming unit, the image forming unit forms an image on only one side ofeach of the sheets, and the sheets each having an image only on its oneside are output to the first sheet output section will be described.

Hereinafter, control in the present embodiment will be described withreference to the flowchart shown in FIG. 24 . Like step numbers areassigned to the same steps as those of the above-described embodiments,and the description thereof is omitted. The image forming process andthe hardware configuration are also the same as those of the eighthembodiment, so the description thereof is omitted.

S3400 to S3405 are the same as those of the eighth embodiment, so thedescription thereof is omitted.

In S3601, the CPU 601 displays a message (c) on the operation panel 626.The content of the message displayed on the operation panel 626 at thistime is, for example, the message shown in FIG. 23C. The message (c) isa message prompting a user to “in a state where a set of sheets outputto the FU tray 116 is turned upside down, put the top sheet one by oneon a set of sheets stacked on the FD tray 115”. The message (c) containsOK button.

In S3602, when the CPU 601 has acquired information that OK button hasbeen depressed by the user, the CPU 601 clears the message (c), and theprocess proceeds to S3603.

The content of the message displayed on the operation panel 626 in S3601assumes the case where about two or three sheets are output to the FUtray 116. Alternatively, in the present embodiment, it is alsoapplicable that only one sheet is output, and the message may be amessage of the content that “turn the sheet output to the FU tray 116upside down and put the sheet on a set of sheets stacked on the FD tray115”.

The CPU 601 may change the content of a message to be displayed on theoperation panel 626 according to whether the number of sheets output tothe FU tray 116 is only one. Furthermore, when there is no subsequentpage, S3602 and the following steps may be omitted.

In S3603, the CPU 601 displays a message (d) on the operation panel 626.The content of the message displayed on the operation panel 626 at thistime is, for example, the message shown in FIG. 23D. The message (d) isa message prompting a user to “close the FU tray 116”. The message (d)also contains OK button. When the CPU 601 has acquired information thatOK button has been depressed by the user, the CPU 601 may clear themessage (d).

In S3604, when the FU tray open/close sensor 117 detects that the FUtray 116 is closed, the process proceeds to S3605.

In S3605, the CPU 601 outputs operation instructions to the sheetconveying mechanism 511, the fixing device 130, and the image formingsection 120 and resumes the printing operation by using the FD tray 115as the sheet output destination in S3405. At this time, sheets output tothe FU tray 116 are also stacked on the FD tray 115. Therefore, the CPU601 causes the image forming unit to form an image subsequent to animage formed on the sheet fed by the sheet feeding unit before theprinting operation is suspended. The number of sheets fed is the numberof sheets passing through the registration sensor 106.

Through the above-described control, when the printing operation on allthe plurality of sheets completes, all the sheets involved in theprinting operation are stacked on the FD tray 115 in order.

The messages (c), (d) are not necessarily displayed on the operationpanel 626. Alternatively, the contents of the messages (c), (d) may beinformed to a user by voice by means of, for example, a readingfunction. Alternatively, the message contents as shown by the messages(c), (d) may be informed to a user by light emitting patterns of an LEDlamp.

In the present embodiment, the case where a different image is formed onone side of each of a plurality of sheets and the FU tray 116 switchesinto the open position while a sheet is output to the FD tray 115 hasbeen described. However, it is not necessarily the case where adifferent image is formed. Alternatively, it may be the case where thesame image is formed on one side of each of a plurality of sheets. Inthis case, in S3601, the message (c) does not need to be provided toprompt the user to correct the stacking order of sheets output to the FUtray 116 and bring the sheets together into a set of sheets stacked onthe FD tray 115. The user may be prompted to put a set of sheets outputto the FU tray 116 onto a set of sheets stacked on the FD tray 115.

In the present embodiment, the case where a different image is formed onone side of each of a plurality of sheets and the FU tray 116 switchesinto the open position while a sheet is output to the FD tray 115 hasbeen described. However, it is not necessarily the case where adifferent image is formed. Alternatively, it may be the case where thesame image is formed on one side of each of a plurality of sheets.

In addition, the case where an image is formed on one side of each of aplurality of sheets has been described. Alternatively, it may be thecase where an image is formed on both sides of each of a plurality ofsheets.

Summary of Ninth Embodiment

As described above, in the present embodiment, the case where theprinting operation to, in the closed state of the FU tray 116, form animage only on one side of each of a plurality of sheets and output asheet to the FD tray 115 has been described. When the FU tray open/closesensor 117 detects that the FU tray 116 is in the open state before thelast sheet of a plurality of sheets is output to the FD tray 115, theCPU 601 cancels feeding of a new sheet and suspends printing operation.The CPU 601 cancels feeding of a new sheet and suspends the printingoperation. Thus, it is possible to suppress continuous output of a sheetto the FU tray 116, and it is possible to reduce the number of sheets tobe output to the FU tray 116 that is not an intended output destination.Subsequently, the message output unit prompts a user to stack and bringtogether the sheets output to the FU tray 116 onto a set of sheetsstacked on the FD tray 115. With this operation, it is possible to bringoutput sheets together into one set while suppressing wrong stackingorder of sheets. Furthermore, it is possible to reduce waste sheetsoutput to the FU tray 116 that is not an intended sheet output tray.

Tenth Embodiment

In the eighth embodiment, when, before the last sheet of a plurality ofsheets is output to the FD tray 115, the FU tray open/close sensor 117detects that the FU tray 116 is in the open state, the CPU 601 cancelsfeeding of a new sheet. Then, the printing operation is suspended.Subsequently, the message output unit prompts a user to remove sheetsoutput to the FU tray 116 and switch the FU tray 116 into the closeposition. When the FU tray open/close sensor 117 detects that the FUtray 116 is in the closed state, the printing operation in which theimage forming unit forms an image again subsequent to the image formedon the last sheet output to the FD tray 115 before the printingoperation is suspended is performed. In other words, reprint isperformed. In the ninth embodiment, when the FU tray open/close sensor117 detects that the FU tray 116 is in the open state before the lastsheet of a plurality of sheets is output to the FD tray 115, the CPU 601cancels feeding of a new sheet. Then, the printing operation issuspended. Subsequently, a user is prompted to stack and bring togetherthe sheets output to the FU tray 116 onto a set of sheets stacked on theFD tray 115.

As in the case of the eighth embodiment, when the CPU 601 reprints onsheets output to the FU tray 116, a user does not need to performburdensome operation that needs to consider the orientation of sheetsand stacking order. As in the case of the ninth embodiment, when sheetsare brought together into one set through user's operation, it isadvantageous that sheets output to the FU tray 116 are not wasted. Whichis better, the case of the eighth embodiment or the case of the ninthembodiment, depends on user convenience. Accordingly, in the presentembodiment, it is possible to allow a user to select whether to reprintas in the case of the eighth embodiment or to prompt the user to bringtogether output sheets into one set without reprinting as in the case ofthe ninth embodiment.

In the tenth embodiment as well, a series of printing operation in whichthe sheet feeding unit feeds a plurality of sheets to the image formingunit, the image forming unit forms an image only on one side of each ofthe sheets, and the sheets are output to the FD tray 115 is performed.Hereinafter, control in the present embodiment will be described withreference to the flowchart shown in FIG. 25 . Like step numbers areassigned to the same steps as those of the above-described embodiments,and the description thereof is omitted. The image forming process andthe hardware configuration are also the same as those of the eighth andninth embodiments, so the description thereof is omitted.

S3400 to S3405 are the same as those of the eighth and ninthembodiments, so the description thereof is omitted. In S3701, the CPU601 displays a message (e) on the operation panel 626. The content ofthe message displayed on the operation panel 626 at this time is, forexample, the message shown in FIG. 23E. The message (e) is a messagemaking a user recognize that the FU tray 116 is opened and prompting theuser to select whether to reprint on sheets output to the FU tray 116.

In S3702, when the CPU 601 has acquired information that YES is selectedby the user (when the user selects to reprint), the process proceeds inorder of S3406 to S3411. S3406 to S3411 are the same as those of theeighth embodiment, so the description thereof is omitted. In S3702, whenthe CPU 601 has acquired information that NO is selected by the user(when the user selects not to reprint), the process proceeds in order ofS3601 to S3605. S3601 to S3605 are the same as those of the ninthembodiment, so the description thereof is omitted.

Summary of Tenth Embodiment

As described above, in the present embodiment, the case where theprinting operation to, in the closed state of the FU tray 116, form animage only on one side of each of a plurality of sheets and outputsheets to the FD tray 115 has been described. When the FU tray 116 isopened and the FU tray open/close sensor 117 detects that the FU tray116 is in the open state, the CPU 601 cancels feeding of a new sheet andsuspends printing operation. The CPU 601 cancels feeding of a new sheetand suspends the printing operation. Thus, it is possible to suppresscontinuous output of a sheet to the FU tray 116, and it is possible toreduce the number of sheets to be output to the FU tray 116 that is notan intended output destination. In addition, it is possible to allow auser to select whether to reprint as in the case of the eighthembodiment or to prompt the user to bring together output sheets intoone set without reprinting as in the case of the ninth embodiment. Withthis function, it is possible to handle both the case where a user wantsto increase convenience by reprinting and the case where the user doesnot want to waste sheets output to the FU tray 116, so the usability isimproved.

Eleventh Embodiment

In the image forming apparatus as described in Japanese Patent Laid-OpenNo. 2000-238959, double-sided printing can be performed when the FU trayis in the closed state. However, when the FU tray is in the open state,a sheet cannot be conveyed to the double-sided printing conveying path,so the image forming apparatus is not able to continue double-sidedprinting. In other words, when double-sided printing is started and thenthe FU tray is switched into the open state, double-sided printingcannot be continued, so this may lead to a decrease in usability. Evenwhen double-sided printing is started and then the FU tray is switchedinto the open state, double-sided printing is enabled to continue.

Automatic Double-Sided Printing Mode and Manual Double-Sided PrintingMode

When the image forming apparatus 20 of the present embodiment performsprinting operation to form an image on both sides of a sheet, the imageforming apparatus 20 has an automatic double-sided printing mode and amanual double-sided printing mode. The automatic double-sided printingmode is also referred to as first double-sided printing method, and themanual double-sided printing mode is also referred to as seconddouble-sided printing method. Hereinafter, each of the modes will bedescribed with reference to FIG. 26A to FIG. 26H.

Automatic Double-Sided Printing Mode

When double-sided printing is performed in the automatic double-sidedprinting mode, the leading edge of a sheet having an image only on itsone side passes through the after-fixing paper presence sensor 110 inthe closed state of the FU tray 116 as shown in, for example, FIG. 26A.As shown in, for example, FIG. 26B, after a lapse of a predeterminedtime from when the trailing edge of the sheet passes through theafter-fixing paper presence sensor 110, the CPU 601 reverses therotation of the stepping motor 623. The predetermined time is a timecalculated by the CPU 601 from the conveying speed of a sheet and adistance from the after-fixing paper presence sensor 110 to the pair ofFD rollers 112. Alternatively, the CPU 601 may start the reverserotation of the stepping motor 623 after a lapse of a time calculatedfrom the conveying speed of a sheet and the length of the sheet fromwhen the FD tray sheet output sensor 125 detects the leading edge of thesheet.

When the rotation of the stepping motor 623 is reversed, the rotation ofthe pair of FD rollers 112 is also reversed as shown in FIG. 26B. Whenthe rotation of the pair of FD rollers 112 is reversed, the conveyingdirection of the sheet is also reversed. The sheet of which theconveying direction is reversed is conveyed from the pair of FD rollers112 to the set of FU rollers 111. When the sheet of which the conveyingdirection is reversed is conveyed to the set of FU rollers 111, thesheet is conveyed to the double-sided printing conveying path L1. Asshown in FIG. 26B, the conveying direction when a sheet is output to theFD tray 115 is also referred to as first direction, and the conveyingdirection when the rotation of the pair of FD rollers 112 is reversed isalso referred to as second direction.

The pair of FD rollers 112 rotates in the first direction to convey asheet to the FD tray 115 and conveys the sheet in the first direction.The pair of FD rollers 112 rotates in the second direction to convey asheet to the image forming unit again and conveys the sheet in thesecond direction. In this way, the pair of FD rollers 112 is capable ofchoosing whether to rotate in the first direction to convey a sheet inthe first direction or to rotate in the second direction to convey asheet in the second direction. In the present embodiment, the pair of FDrollers 112 is also referred to as first sheet output conveying unit.

In addition, after a sheet is conveyed in the second direction by thepair of FD rollers 112, the set of FU rollers 111 conveys the sheetsubsequently to the pair of FD rollers 112 in the conveying pathdownstream in the second direction from the FU tray 116 serving as aguiding portion. When the sheet reaches the set of FU rollers 111, theset of FU rollers 111 conveys the sheet to the double-sided printingconveying path L1 even when the FU tray 116 is in the open state. In thepresent embodiment, the set of FU rollers 111 is also referred to assecond sheet output conveying unit.

The sheet conveyed to the double-sided printing conveying path L1 passesthrough the double-sided printing conveying sensor 113 and is conveyedto the pair of conveying rollers 105 by the pair of double-sidedprinting conveying rollers 114. When the sheet is conveyed from the pairof double-sided printing conveying rollers 114 to the pair of conveyingrollers 105, the upper surface and lower surface of the sheet are turnedupside down, and the sheet is conveyed again to the image forming unitin a state where the surface having an image faces downward. For thesheet conveyed again to the image forming unit, an image is formed onthe surface having no image and fixed, and the sheet is output to the FDtray 115. An image formed on a front surface is also referred to asfirst image, and an image formed on a surface having no image (alsoreferred to as back surface) is also referred to as second image.

As described above, in the automatic double-sided printing mode, the CPU601 causes the pair of FD rollers 112 to switch the conveying directionof a sheet having a first image only on its one side to the seconddirection in a state where the FU tray 116 is closed. The CPU 601 causesthe sheet having the first image only on its one side to be conveyed inthe second direction to the image forming unit again to form a secondimage on the sheet having the first image only on its one side.

In other words, the automatic double-sided printing mode is a printingoperation in which the CPU 601 causes the image forming unit toalternately form an image on the front surface of a sheet and an imageon the back surface of the sheet.

Manual Double-Sided Printing Mode

In the case where double-sided printing is performed in the manualdouble-sided printing mode, when a sheet having an image only on its oneside is output to the FD tray 115 in a state where the FU tray 116 isclosed, the CPU 601 suspends the printing operation. In a state wherethe FU tray 116 is open, when a sheet having an image on its one side isoutput to the FU tray 116, the CPU 601 suspends the printing operation.

Subsequently, a user needs to perform operation as will be describedbelow. In the present embodiment, a message as shown in FIG. 29A or FIG.29B or a message as shown in FIG. 29C or FIG. 29D may be output by themessage output unit.

Initially, a user stacks a sheet on the MP tray 140 such that the imagesurface of a sheet having an image on its one side and output to the FDtray 115 or the FU tray 116 faces downward. When the sheet having animage on its one side is stacked on the MP tray 140 by the user, the CPU601 resumes the suspended printing operation. The sheet stacked on theMP tray 140 by the user is conveyed again to the image forming unit bythe MP sheet feeding roller 142. For the sheet conveyed again to theimage forming unit, a toner image is formed on the surface having noimage and fixed, and then the sheet is output to the FD tray 115 or theFU tray 116.

As described above, in the manual double-sided printing mode, the CPU601 causes the sheet having an image only on its one side to be outputto the FD tray 115 or the FU tray 116. As a result of the fact that thesheet output to the FU tray 116 is stacked on the sheet feeding unit,the CPU 601 conveys the sheet again to the image forming unit and formsa second image on the sheet having a first image only on its one side.

In other words, in the manual double-sided printing mode, the printingoperation is such that the CPU 601 causes the image forming unit to forman image on the front surface of each of a plurality of sheets on whichan image is to be formed and then to form an image on the back surfaceof each of the plurality of sheets on which an image is to be formed. Inthe manual double-sided printing mode, the printing operation in whichthe CPU 601 causes the image forming unit to form an image on the frontsurface of each of a plurality of sheets and then to form an image onthe back surface of each of the plurality of sheets may be performed inmultiple steps. In this case, the CPU 601 may cause the operation panel626 to output a message making a user provide information about how manysheets output to the FD tray 115 or the FU tray 116 are stacked on theMP tray 140.

In the present embodiment, the manual double-sided printing mode doesnot need to be provided.

When FU Tray 116 is Opened During Double-Sided Printing in AutomaticDouble-Sided Printing Mode

Hereinafter, the case where the FU tray 116 is opened duringdouble-sided printing in the automatic double-sided printing mode willbe described with reference to FIG. 26A to FIG. 26H. When double-sidedprinting is performed in the automatic double-sided printing mode, asheet having an image only on its one side is conveyed in the seconddirection. FIG. 26C shows a state where the sheet approaches the set ofFU rollers 111. When the FU tray 116 is opened by a user before thesheet approaches the set of FU rollers 111, the sheet is output to theFD tray 115 or the FU tray 116. In this case, whether the sheet isoutput to the FD tray 115 or the FU tray 116 varies depending on anabnormality detection method used at the time when the CPU 601 detectsan abnormality and suspends the printing operation. In the presentembodiment, the CPU 601 detects an abnormality with a first abnormalitydetection method and suspends the printing operation.

First Abnormality Detection Method

The first abnormality detection method with which the CPU 601 suspendsthe printing operation is such that a sheet is not detected by thedouble-sided printing conveying sensor 113 after a lapse of a certaintime from when the pair of FD rollers 112 starts reverse rotation. Inthis case, even when a certain time has elapsed from when the pair of FDrollers 112 starts reverse rotation, the double-sided printing conveyingsensor 113 does not transmit a LOW signal and continues outputting aHIGH signal. Until the double-sided printing conveying sensor 113transmits a LOW signal, the CPU 601 performs printing operation asnormal. A method of transmitting a signal with the double-sided printingconveying sensor 113 is similar to the above-described method ofdetecting a sheet with the after-fixing paper presence sensor 110, sothe detailed description is omitted here.

For example, after a sheet having a first image only on its one sideapproaches the pair of FD rollers 112 as shown in FIG. 26B, the pair ofFD rollers 112 starts reverse rotation, and the FU tray 116 is opened asshown in FIG. 26D before the sheet is conveyed in the second direction.In this case, the double-sided printing conveying sensor 113 does nottransmit a LOW signal, and the CPU 601 does not detect an abnormality,so the pair of FD rollers 112 starts reverse rotation as normal andconveys the sheet in the second direction. Therefore, the sheet conveyedin the second direction is output to the FU tray 116 as shown in FIG.26F. When the sheet is output to the FU tray 116, the double-sidedprinting conveying sensor 113 continues transmitting a HIGH signal tothe CPU 601 even after a lapse of a certain time from when the pair ofFD rollers 112 starts reverse rotation. Therefore, the CPU 601 detectsan abnormality and suspends the printing operation.

When the sheet approaches the set of FU rollers 111 and then the FU tray116 is opened as shown in FIG. 26E, the sheet is conveyed to thedouble-sided printing conveying path L1, so a second image is formed onthe sheet by the image forming unit.

Process in Case where FU Tray 116 is Opened During Double-Sided Printing

Next, a specific process in the present embodiment will be describedwith reference to the flowcharts of FIG. 27A and FIG. 27B. In thepresent embodiment, the case where the CPU 601 performs double-sidedprinting in the automatic double-sided printing mode in a state wherethe FU tray 116 is closed and suspends the printing operation with thefirst abnormality detection method will be described. The firstabnormality detection method is as described above. In the presentembodiment, the case where one sheet is subjected to double-sidedprinting will be described. S4101 may be started from a state where nosheet has been output to the FU tray 116, or S4101 may be started from astate where one or more sheets have been output to the FU tray 116.

In S4101, when the leading edge of a sheet having an image on its oneside reaches the after-fixing paper presence sensor 110 as shown in FIG.26A and the CPU 601 receives a LOW signal output from the after-fixingpaper presence sensor 110, the process proceeds to S4102. Detection of asheet has been described in the method of detecting a sheet with theafter-fixing paper presence sensor 110, so the detailed description isomitted here.

In S4102, when the FU tray 116 is opened by user's operation and the CPU601 receives a HIGH signal output from the FU tray open/close sensor117, the process proceeds to S4109. When the CPU 601 does not receive aHIGH signal output from the FU tray open/close sensor 117, the processproceeds to S4103.

In S4103, when the leading edge of a sheet having an image on its oneside reaches the FD tray sheet output sensor 125 and the CPU 601receives a LOW signal output from the FD tray sheet output sensor 125,the process proceeds to S4108. When the CPU 601 does not receive a LOWsignal output from the FD tray sheet output sensor 125, the processreturns to S4102.

In S4104, when the FU tray 116 is opened by user's operation and the CPU601 receives a HIGH signal output from the FU tray open/close sensor117, the process proceeds to S4108. When the CPU 601 does not receive aHIGH signal output from the FU tray open/close sensor 117, the processproceeds to S4105.

In S4105, when the CPU 601 acquires information that the rotation of thestepping motor 623 is reversed, the process proceeds to S4106. When therotation of the stepping motor 623 is reversed, the sheet is conveyed inthe second direction as shown in FIG. 26D. When the CPU 601 does notacquire information that the rotation of the stepping motor 623 isreversed, the process returns to S4104.

In S4106, when the FU tray 116 is opened by user's operation and the CPU601 receives a HIGH signal output from the FU tray open/close sensor117, the process proceeds to S4109. When the CPU 601 does not receive aHIGH signal output from the FU tray open/close sensor 117, the processproceeds to S4107.

In S4107, when the leading edge of the sheet having an image on its oneside reaches the set of FU rollers 111 as shown in FIG. 26E, the sheethaving an image on its one side is conveyed to the double-sided printingconveying path L1. For the sheet having an image on its one side andconveyed to the double-sided printing conveying path L1, a second imageis formed on a surface having no image, the sheet is output to the FDtray 115, and then the process ends. When the leading edge of the sheethaving an image on its one side has not reached the set of FU rollers111, the process returns to S4106.

In S4108, when the CPU 601 acquires information that the rotation of thestepping motor 623 is reversed, the process proceeds to S4109. When therotation of the stepping motor 623 is reversed, a sheet is conveyed inthe second direction as shown in FIG. 26D.

In S4109, the sheet having an image on its one side is output to the FUtray 116. When the sheet is output to the FU tray 116, the CPU 601 doesnot receive a LOW signal output from the double-sided printing conveyingsensor 113 even after a lapse of a certain time from when the pair of FDrollers 112 starts reverse rotation. Therefore, the CPU 601 detects thatan abnormality has occurred and causes the sheet feeding unit to cancelfeeding of a new sheet, and the process proceeds to S4110. S4104, S4105,S4106, S4108, and S4109 are steps corresponding to the above-describedfirst abnormality detection method.

Whether a sheet is output to the FU tray 116 is determined in accordancewith whether the trailing edge of the sheet passes through the FD traysheet output sensor 125 before a lapse of a predetermined time from whenthe trailing edge of the sheet passes through the after-fixing paperpresence sensor 110. When the CPU 601 does not receive a LOW signaloutput from the FD tray sheet output sensor 125, the CPU 601 detectsthat the sheet is output to the FU tray 116. Here, the predeterminedtime is a time calculated by using the conveying speed of a sheet and adistance from the after-fixing paper presence sensor 110 to the FD traysheet output sensor 125.

In S4110, the CPU 601 causes the operation panel 626 to output a messageprompting the user to perform operation described below, and the processproceeds to S4111.

The operation that the CPU 601 prompts the user to perform in themessage output to the operation panel 626 in S4110 will be described.Initially, a sheet output to the FU tray 116 is turned upside down intoa state where the surface having an image faces downward. In a statewhere the surface having no image faces upward, the sheet is stackedonto the MP tray 140 such that the leading edge of the sheet output tothe FU tray 116 is inserted to the MP tray 140. A message to bedisplayed at this time may be, for example, the sentence shown in FIG.29A or may be, for example, the picture shown in FIG. 29B.Alternatively, in order for a user to easily understand necessaryoperation, for example, the picture shown in FIG. 29B may be animatedand displayed on the operation panel 626.

The CPU 601 is able to continue double-sided printing by causing themessage output unit to output such a message and prompting a user toperform operation, so the usability is improved. The message displayedin S4110 may contain OK button. OK button is a button to be depressed atthe time when the user has completed operation according to the message.When OK button is depressed, the CPU 601 acquires a signal indicatingthat the operation is complete. OK button may be a button that indicatescompletion of operation, such as “COMPLETE” button.

In S4111, the CPU 601 suspends the printing operation, and the processproceeds to S4112. The order of the processes of S4110 and S4111 may beinterchanged.

In S4112, when the sheet is stacked on the MP tray 140 by the user andthe CPU 601 acquires a LOW signal output from the MP paper presencesensor 141, the process proceeds to S4113. Information indicatingwhether a sheet is stacked on the MP tray 140 is not necessarily outputfrom the MP paper presence sensor 141. Alternatively, a user may make aninput through the keypad of the operation panel 626 to outputinformation that a sheet is stacked on the MP tray 140.

In S4113, when the CPU 601 has acquired information that OK buttoncontained in the message displayed on the operation panel 626 has beendepressed by the user, the process proceeds to S4114.

In S4114, the CPU 601 resumes the printing operation. Specifically, theCPU 601 resumes feeding of a sheet stacked on the MP tray 140, forms asecond image on the surface having no image, outputs the sheet to the FUtray 116, and then the process ends.

In the present embodiment, the case where a sheet is conveyed in shortedge feeding and double-sided printing is performed in long side bindinghas been described. Therefore, when a user is prompted to stack a sheeton the MP tray 140, the user is prompted to “stack a sheet onto the MPtray 140 such that the leading edge of the output sheet is inserted tothe MP tray 140”. Alternatively, the case where a sheet is conveyed inshort edge feeding and double-sided printing is performed in short sidebinding is applicable. When double-sided printing is performed in shortside binding, a user is prompted to “stack a sheet onto the MP tray 140such that the trailing edge of the output sheet is inserted to the MPtray 140”.

Summary of Eleventh Embodiment

As described above, in the present embodiment, the case wheredouble-sided printing is performed on a sheet and the FU tray 116 isswitched into the open state after double-sided printing is started hasbeen described. In addition, the case where the CPU 601 suspendsprinting operation with the first abnormality detection method has beendescribed.

In the present embodiment, before a sheet having a first image only onits one side approaches the set of FU rollers 111, the FU tray 116 isopened by a user, and the sheet is output to the FU tray 116. The CPU601 causes the message output unit to output a message prompting theuser to manually stack the output sheet onto the MP tray 140. Inresponse to the fact that the output sheet is stacked on the MP tray 140by the user, the CPU 601 resumes sheet feeding with the sheet feedingunit and causes the image forming unit to form a second image. With thisfunction, even when the FU tray 116 is switched into the open stateafter double-sided printing is started, it is possible to continuedouble-sided printing. It is possible to perform double-sided printingdesired by a user by not wasting an output sheet having an image only onits one side and forming an image on the surface having no image.

Twelfth Embodiment

In the eleventh embodiment, the case where, when double-sided printingis performed on a sheet, double-sided printing can be continued evenwhen the FU tray 116 is opened during double-sided printing in theautomatic double-sided printing mode has been described. In the presentembodiment, the case where double-sided printing is performed on aplurality of sheets will be described.

In the present embodiment, as in the case of the eleventh embodiment,the CPU 601 suspends printing operation with the first abnormalitydetection method. The first abnormality detection method is as describedabove. When a sheet output to the FU tray 116 is stacked on the MP tray140 by a user, a second image is formed on the surface having no image,and double-sided printing for one sheet completes. In the presentembodiment, the case where, after double-sided printing for one sheet iscomplete, a user is able to select whether to maintain the automaticdouble-sided printing mode until printing of subsequent images (alsoreferred to as pages) ends or to switch to the printing operation in themanual double-sided printing mode will be described.

Hereinafter, control in the present embodiment will be described withreference to the flowcharts shown in FIG. 28A to FIG. 28C. Like stepnumbers are assigned to the same steps as those of the above-describedembodiments, and the description thereof is omitted. The image formingprocess and the hardware configuration are also the same as those of theeleventh embodiment, so the description thereof is omitted. S4101 toS4114 in the flowcharts of FIG. 28A to FIG. 28C are the same as those ofthe eleventh embodiment.

In S4210, when the CPU 601 receives information on subsequent imagesfrom the printer controller 213, the process proceeds to S4211. When theCPU 601 does not receive information on subsequent images from theprinter controller 213, the process ends.

In S4211, when the information on subsequent images, received by the CPU601, contains only one subsequent image, the process proceeds to S4212,the CPU 601 causes the image forming unit to form an image on one sideof the sheet, and the process ends. When the information on subsequentimages, received by the CPU 601, contains two or more subsequent images,the process of the flowchart shown from [1] is executed.

In S4213, the CPU 601 causes the operation panel 626 to output a messageas will be described below. The message is a message prompting a user toselect whether to maintain the automatic double-sided printing modeuntil printing of subsequent images ends or to switch to the manualdouble-sided printing mode. At this time, for example, the message shownin FIG. 30A is displayed on the operation panel 626. The user selectsone in response to the message and operates the operation panel 626. Theoperation panel 626 outputs information about the double-sided printingmode, selected by user's operation, and the process proceeds to the nextstep.

When the CPU 601 causes the message output unit to output such amessage, double-sided printing can be maintained by using a double-sidedprinting mode desired by the user, and the usability is improved.

In S4213, when the CPU 601 has acquired information indicating that aprocess to “perform double-sided printing for subsequent images in theautomatic double-sided printing mode” is selected by the user, theprocess proceeds to S4214.

In S4214, the CPU 601 causes the message output unit to output a messageprompting the user to close the FU tray 116 on the operation panel 626,and the process proceeds to S4215. At this time, for example, themessage shown in FIG. 30F is displayed on the operation panel 626.

In S4215, when the FU tray 116 is opened by the user and the CPU 601receives a LOW signal output from the FU tray open/close sensor 117, theprocess proceeds to S4216. Before the CPU 601 receives a LOW signaloutput from the FU tray open/close sensor 117, the process returns toS4214, and the CPU 601 causes the message output unit to output theabove-described message on the operation panel 626.

In S4216, the CPU 601 resumes double-sided printing in the automaticdouble-sided printing mode, and ends printing. The automaticdouble-sided printing mode has been described in Automatic Double-SidedPrinting Mode, so the detailed description is omitted here.

In S4213, when the CPU 601 has acquired information indicating that aprocess to “perform double-sided printing for subsequent images in themanual double-sided printing mode” is selected by the user, the processproceeds to S4217.

In S4217, the printer controller 213 cancels the printing operation inthe automatic double-sided printing mode for subsequent images generatedat the start of printing, and switches the printing operation into theprinting operation in the manual double-sided printing mode.

Method of Switching from Printing Operation in Automatic Double-SidedPrinting Mode to Printing Operation in Manual Double-Sided Printing Mode

Hereinafter, a method with which the printer controller 213 switchesfrom the printing operation in the automatic double-sided printing modeto the printing operation in the manual double-sided printing mode willbe described.

Initially, the printing operation in the automatic double-sided printingmode and the printing operation in the manual double-sided printing modewill be described. When, for example, images of consecutive eight pagesare printed on both sides of four sheets, the CPU 214 of the printercontroller 213 outputs image signals that are pieces of second imageinformation in the order shown in FIG. 30B to the printing section 221in the automatic double-sided printing mode. In accordance with theimage signals output by the CPU 214, the CPU 601 causes the imageforming unit to alternately form an image on the front surface and animage on the back surface.

In the manual double-sided printing mode, the CPU 214 of the printercontroller 213 outputs image signals that are pieces of second imageinformation in the order shown in FIG. 30C to the printing section 221.In accordance with the image signals output by the CPU 214, the CPU 601causes the image forming unit to form an image on all the front surfacesof the sheets on which an image is to be formed and then to form animage on all the back surfaces of the sheets on which an image is to beformed. The CPU 601 may execute in multiple steps the printing operationin which the image forming unit forms an image on the front surfaces ofa plurality of sheets on which an image is to be formed and then formsan image on the back surfaces of the plurality of sheets on which animage is to be formed.

In the case of the manual double-sided printing mode, initially, inaccordance with the image signals output by the CPU 214, the CPU 601causes the image forming unit to form an image on the front surfaces offour sheets and then output the sheets to the FU tray 116. When the foursheets each having an image only on its front surface are output to theFU tray 116, the CPU 601 causes the operation panel 626 to output amessage prompting the user to stack the sheets onto the MP tray 140. Amessage to be displayed at this time may be, for example, the sentenceshown in FIG. 30D or may be, for example, the picture shown in FIG. 30E.Alternatively, in order for a user to easily understand necessaryoperation, for example, the picture shown in FIG. 30E may be animatedand displayed on the operation panel 626. When the user stacks a set ofsheets onto the MP tray 140 in response to the message and the CPU 601acquires information that OK button has been depressed, the CPU 601causes the sheet feeding unit to resume paper feeding and causes theimage forming unit to form an image on the surface, having no image, ofeach sheet.

In this way, between the automatic double-sided printing mode and themanual double-sided printing mode, the order in which the CPU 214 of theprinter controller 213 outputs image signals that are pieces of secondimage information to the printing section 221 is different.

S4217 will be further described. When, for example, the CPU 601completes double-sided printing up to the fourth page out of 10-pageprinting operation and then the process proceeds to S4217, the printercontroller 213 cancels the printing operation for double-sided printingof the fifth to tenth pages generated at the start of printing.Subsequently, since the leading page of the remaining fifth to tenthpages is an odd-number page, the image signals for the odd-number pagesare sorted in ascending order and are output to the printing section221. In other words, the printer controller 213 outputs the imagesignals for fifth, seventh, and ninth pages to the printing section 221.The CPU 601 causes the image forming unit to form images of the fifth,seventh, and ninth pages and outputs three sheets each having an imageonly on its one side to the FU tray 116. When printing of the odd-numberpages ends, the CPU 601 causes the operation panel 626 to display amessage prompting the user to stack the set of sheets onto the MP tray140. When the user stacks the set of sheets onto the MP tray 140 inresponse to the message and the CPU 601 acquires information that OKbutton has been depressed, the printer controller 213 sorts imagesignals for the even-number pages in ascending order and outputs theimage signals to the printing section 221. The CPU 601 causes the imageforming unit to form images of the sixth, eighth, and tenth pages,outputs the three sheets each having an image on each side to the FUtray 116, and ends printing.

Summary of Twelfth Embodiment

As described above, in the present embodiment, the case wheredouble-sided printing is performed on a plurality of sheets and the FUtray 116 is switched into the open state after double-sided printing isstarted has been described. In addition, the case where the CPU 601suspends printing operation with the first abnormality detection methodhas been described.

In the present embodiment, before a sheet having a first image only onits one side approaches the set of FU rollers 111, the FU tray 116 isopened by a user, and the sheet is output to the FU tray 116. The CPU601 causes the message output unit to output a message prompting theuser to manually stack the output sheet onto the MP tray 140. Inresponse to the fact that the output sheet is stacked onto the MP tray140 by the user, the CPU 601 resumes paper feeding with the sheetfeeding unit and causes the image forming unit to form a second image.With this function, even when the FU tray 116 is switched into the openstate after double-sided printing is started, it is possible to continuedouble-sided printing. It is possible to perform double-sided printingdesired by a user by not wasting an output sheet having an image only onits one side and forming an image on the surface having no image.

In addition, at the time of printing subsequent images, it is possibleto make a user close the FU tray 116 and resume printing in theautomatic double-sided printing mode without changing the printing mode.Alternatively, at the time of printing subsequent images, it is possibleto switch the printing operation into the manual double-sided printingmode by the printer controller 213 while the FU tray 116 remains openand resume printing in the manual double-sided printing mode. With thisfunction, even when a user erroneously opens the FU tray 116 after thestart of printing, double-sided printing can be continued by using adouble-sided printing mode desired by the user, so the usability isimproved.

Thirteenth Embodiment

In the eleventh and twelfth embodiments, the case where the CPU 601suspends printing operation with the first abnormality detection methodhas been described. In the present embodiment, the case where theprinting operation is suspended with a second abnormality detectionmethod will be described. The second abnormality detection method willbe described later.

In the present embodiment, as in the case of the eleventh and twelfthembodiments, the case where double-sided printing is performed in theautomatic double-sided printing mode in a state where the FU tray 116 isclosed will be described. As in the case of the eleventh embodiment, thecase where double-sided printing is performed on a sheet and the FU tray116 is switched into the open state after double-sided printing isstarted will be described.

Second Abnormality Detection Method

The second abnormality detection method with which the CPU 601 suspendsthe printing operation is such that the FU tray 116 is opened by a userand a second signal is output from the FU tray open/close sensor 117.

When, for example, the FU tray 116 is opened before a sheet having afirst image only on its one side approaches the pair of FD rollers 112,the sheet having the first image only on its one side is output to theFU tray 116 as shown in FIG. 26G. When a sheet having a first image onlyon its one side approaches the pair of FD rollers 112 and then the FUtray 116 is opened before the pair of FD rollers 112 starts reverserotation, the CPU 601 suspends printing operation. Therefore, the sheethaving the first image only on its one side is output to the FD tray 115as shown in FIG. 26H. In addition, when the FU tray 116 is opened beforethe pair of FD rollers 112 starts reverse rotation and the sheet ofwhich the conveying direction is reversed is conveyed to the set of FUrollers 111, the sheet having a first image only on its one side isoutput to the FU roller 116 as shown in FIG. 26F.

Hereinafter, control in the present embodiment will be described withreference to the flowcharts shown in FIG. 31A and FIG. 31B. Like stepnumbers are assigned to the same configuration as those of theabove-described embodiments, and the description thereof is omitted. Theimage forming process and the hardware configuration are also the sameas those of the eleventh and twelfth embodiment, so the descriptionthereof is omitted. S4101 may be started from a state where no sheet hasbeen output to the FU tray 116 or the FD tray 115, or S4101 may bestarted from a state where one or more sheets have been output to the FUtray 116 or the FD tray 115.

In S4301, when the FU tray 116 is opened by user's operation and the CPU601 receives a HIGH signal output from the FU tray open/close sensor117, the CPU 601 detects that an abnormality has occurred. When the CPU601 detects that an abnormality has occurred, the CPU 601 causes thesheet feeding unit to cancel feeding of a new sheet, and the processproceeds to S4304. When the CPU 601 does not receive a second signaloutput from the FU tray open/close sensor 117, the process proceeds toS4103. The description of S4103 is omitted.

In S4302, when the FU tray 116 is opened by user's operation and the CPU601 receives a HIGH signal output from the FU tray open/close sensor117, the CPU 601 detects that an abnormality has occurred. When the CPU601 detects that an abnormality has occurred, the CPU 601 causes thesheet feeding unit to cancel feeding of a new sheet, and the processproceeds to S4306. When the CPU 601 does not receive a HIGH signaloutput from the FU tray open/close sensor 117, the process proceeds toS4105. The description of S4105 is omitted.

In S4303, when the FU tray 116 is opened by user's operation and the CPU601 receives a HIGH signal output from the FU tray open/close sensor117, the CPU 601 detects that an abnormality has occurred. When the CPU601 detects that an abnormality has occurred, the CPU 601 causes thesheet feeding unit to cancel feeding of a new sheet, and the processproceeds to S4304. When the CPU 601 does not receive a HIGH signaloutput from the FU tray open/close sensor 117, the process proceeds toS4107. The description of S4107 is omitted.

In S4304, the sheet having an image on its one side is output to the FUtray 116, and the process proceeds to S4305.

The operation that the CPU 601 prompts the user to perform in themessage output to the operation panel 626 in S4305 will be described.Initially, a sheet output to the FU tray 116 is turned upside down intoa state where the surface having an image faces downward. In a statewhere the surface having no image faces upward, the sheet is stackedonto the MP tray 140 such that the leading edge of the sheet output tothe FU tray 116 is inserted to the MP tray 140. A message to bedisplayed at this time may be, for example, the sentence shown in FIG.29A or may be, for example, the picture shown in FIG. 29B.Alternatively, in order for a user to easily understand necessaryoperation, for example, the picture shown in FIG. 29B may be animatedand displayed on the operation panel 626.

The CPU 601 is able to continue double-sided printing by causing themessage output unit to output such a message and prompting a user toperform operation, so the usability is improved.

In S4306, the sheet having an image on its one side is output to the FDtray 115, and the process proceeds to S4307. S4103, S4105, S4107, S4301,S4302, S4303, S4304, and S4306 are steps corresponding to theabove-described second abnormality detection method.

In S4307, the CPU 601 causes the operation panel 626 to output a messageprompting the user to perform operation described below, and the processproceeds to S4111.

The operation that the CPU 601 prompts the user to perform in themessage output to the operation panel 626 in S4307 will be described.While the upper surface and lower surface of the sheet output to the FDtray 115 remain unchanged, and the sheet is stacked onto the MP tray 140such that the leading edge of the sheet output to the FD tray 115 isinserted to the MP tray 140. A message to be displayed at this time maybe, for example, the sentence shown in FIG. 29C or may be, for example,the picture shown in FIG. 29D. Alternatively, in order for a user toeasily understand necessary operation, for example, the picture shown inFIG. 29D may be animated and displayed on the operation panel 626.

The CPU 601 is able to continue double-sided printing by causing themessage output unit to output such a message and prompting a user toperform operation, so the usability is improved.

The messages displayed in S4305 and S4307 may contain OK button. OKbutton is a button to be depressed at the time when the user hascompleted operation according to the message. When OK button isdepressed, the CPU 601 acquires a signal indicating that the operationis complete. OK button may be a button that indicates completion ofoperation, such as “COMPLETE” button.

In S4111, the CPU 601 suspends the printing operation, and the processproceeds to S4112. The order of the processes of S4305 and S4111 and theorder of the processes of S4307 and S4111 may be interchanged.

S4112 to S4114 are the same as those of the eleventh and twelfthembodiments, so the description thereof is omitted.

Summary of Thirteenth Embodiment

As described above, in the present embodiment, the case wheredouble-sided printing is performed on a sheet and the FU tray 116 isswitched into the open state after double-sided printing is started hasbeen described. In addition, the case where the CPU 601 suspendsprinting operation with the second abnormality detection method has beendescribed.

In the present embodiment, before a sheet having a first image only onits one side approaches the set of FU rollers 111, the sheet is outputto the FU tray 116 or the FD tray 115 according to the timing when theFU tray 116 is opened by a user. The message output unit is caused tooutput a message prompting the user to manually stack the output sheetonto the MP tray 140. In response to the fact that the sheet output tothe FU tray 116 or the FD tray 115 is stacked onto the MP tray 140 bythe user, the sheet feeding unit is caused to resume paper feeding andthe image forming unit is caused to form a second image. With thisfunction, even when the FU tray 116 is switched into the open stateafter double-sided printing is started, it is possible to continuedouble-sided printing. It is possible to perform double-sided printingdesired by a user by not wasting an output sheet having an image only onits one side and forming an image on the surface having no image.

Fourteenth Embodiment

In the eleventh and thirteenth embodiments, the case where, whendouble-sided printing is performed on one sheet, double-sided printingcan be continued even when the FU tray 116 is opened during double-sidedprinting in the automatic double-sided printing mode has been described.In the present embodiment, the case where double-sided printing isperformed on a plurality of sheets will be described.

In the present embodiment, as in the case of the thirteenth embodiment,the printing operation is suspended with the second abnormalitydetection method. The second abnormality detection method is asdescribed above. When a sheet output to the FU tray 116 or the FD tray115 is stacked on the MP tray 140 by user's operation, a second image isformed on the surface having no image, and double-sided printing for onesheet completes. In the present embodiment, the case where, afterdouble-sided printing for one sheet is complete, a user is able toselect whether to maintain the automatic double-sided printing modeuntil printing of subsequent images ends or to switch to the printingoperation in the manual double-sided printing mode will be described.

Hereinafter, control in the present embodiment will be described withreference to the flowchart shown in FIG. 32A to FIG. 32C. Like stepnumbers are assigned to the same configuration as those of theabove-described embodiments, and the description thereof is omitted. Theimage forming process and the hardware configuration are also the sameas those of the eleventh to thirteenth embodiments, so the descriptionthereof is omitted. S4101 to S4114 and S4301 to S4307 in the flowchartof FIG. 32A to FIG. 32C are the same as those of the thirteenthembodiment, so the description thereof is omitted.

In S4210, when the CPU 601 receives information on subsequent imagesfrom the printer controller 213, the process proceeds to S4211. When theCPU 601 does not receive information on subsequent images from theprinter controller 213, the process ends.

In S4211, when the information on subsequent images, received by the CPU601, contains only one subsequent image, the process proceeds to S4212,the CPU 601 causes the image forming unit to form an image on one sideof the sheet, and the process ends. When the information on subsequentimages, received by the CPU 601, contains two or more subsequent images,the process of the flowchart shown from [2] is executed.

In S4213, the CPU 601 causes the operation panel 626 to output a messageas will be described below. The message is a message prompting a user toselect whether to maintain the automatic double-sided printing modeuntil printing of subsequent images ends or to switch to the manualdouble-sided printing mode. At this time, for example, the message shownin FIG. 30A is displayed on the operation panel 626. The user selectsone in response to the message and operates the operation panel 626. Theoperation panel 626 outputs information about the double-sided printingmode, selected by user's operation, and the process proceeds to the nextstep.

When the CPU 601 causes the message output unit to output such amessage, double-sided printing can be maintained by using a double-sidedprinting mode desired by the user, and the usability is improved.

In S4213, when the CPU 601 has acquired information indicating that aprocess to “perform double-sided printing for subsequent images in theautomatic double-sided printing mode” is selected by the user, theprocess proceeds to S4214.

In S4214, the CPU 601 causes the message output unit to output a messageprompting the user to close the FU tray 116 on the operation panel 626,and the process proceeds to S4215. At this time, for example, themessage shown in FIG. 30F is displayed on the operation panel 626.

In S4215, when the FU tray 116 is opened by the user and the CPU 601receives a LOW signal output from the FU tray open/close sensor 117, theprocess proceeds to S4216. Before the CPU 601 receives a LOW signaloutput from the FU tray open/close sensor 117, the process returns toS4214, and the CPU 601 causes the message output unit to output theabove-described message on the operation panel 626.

In S4216, the CPU 601 resumes double-sided printing in the automaticdouble-sided printing mode, and ends printing. The automaticdouble-sided printing mode has been described in Automatic Double-SidedPrinting Mode, so the detailed description is omitted here.

In S4213, when the CPU 601 has acquired information indicating that aprocess to “perform double-sided printing for subsequent images in themanual double-sided printing mode” is selected by the user, the processproceeds to S4217.

In S4217, the printer controller 213 cancels the printing operation inthe automatic double-sided printing mode for subsequent images generatedat the start of printing. The printer controller 213 switches theprinting operation in the automatic double-sided printing mode to theprinting operation in the manual double-sided printing mode, performsdouble-sided printing by using the manual double-sided printing mode,and ends printing.

Summary of Fourteenth Embodiment

As described above, in the present embodiment, the case wheredouble-sided printing is performed on a plurality of sheets and the FUtray 116 is switched into the open state after double-sided printing isstarted has been described. In addition, the case where the CPU 601suspends printing operation with the second abnormality detection methodhas been described.

In the present embodiment, before a sheet having a first image only onits one side approaches the set of FU rollers 111, the sheet is outputto the FU tray 116 or the FD tray 115 according to the timing when theFU tray 116 is opened by a user. The message output unit is caused tooutput a message prompting the user to manually stack the output sheetonto the MP tray 140. In response to the fact that the sheet output tothe FU tray 116 or the FD tray 115 is stacked onto the MP tray 140 bythe user, the sheet feeding unit is caused to resume paper feeding andthe image forming unit is caused to form a second image. With thisfunction, even when the FU tray 116 is switched into the open stateafter double-sided printing is started, it is possible to continuedouble-sided printing. It is possible to perform double-sided printingdesired by a user by not wasting a sheet having an image only on its oneside and forming an image on the other side.

In addition, at the time of printing subsequent images, it is possibleto make a user close the FU tray 116 and resume printing in theautomatic double-sided printing mode without changing the printing mode.Alternatively, at the time of printing subsequent images, it is possibleto switch the printing operation into the manual double-sided printingmode by the printer controller 213 while the FU tray 116 remains openand resume printing in the manual double-sided printing mode. With thisfunction, after the start of printing, even when a user erroneouslyopens the FU tray 116 after the start of printing, double-sided printingcan be continued by using a double-sided printing mode desired by theuser, so the usability is improved.

Fifteenth Embodiment

Japanese Patent Laid-Open No. 2006-168887 describes a configuration thatincludes a plurality of conveying paths and that conveys a sheet byusing one of the plurality of conveying paths. There is, for example, asheet feeding cassette that is a sheet feeding unit that feeds a sheetby using a sheet feed conveying path to convey the sheet to an imageforming unit in a state where the upper surface of the sheet stackedfaces downward. On the other hand, there is a multi-purpose tray(hereinafter, also referred to as MP tray) that is a sheet feeding uniton which a sheet can be stacked by hand and that feeds a sheet by usinga sheet feed conveying path to convey the sheet to the image formingunit while the upper surface of the sheet stacked faces upward. A useris able to switch a sheet feeding section according to usage.

In addition, there is a double-sided printing method that, for example,when double-sided printing is performed, uses a double-sided printingconveying path that switches the conveying direction before conveyingand outputting a sheet having an image on its first surface to an FDtray and then conveys the sheet to the image forming unit again. On theother hand, there is a double-sided printing method that feeds a sheetfrom the MP tray, that makes a user stack the sheet having an image onits first surface and output to an FU tray, and that forms an image onthe second surface without using the double-sided printing conveyingpath. A user is able to switch the double-sided printing methodaccording to usage.

However, in an image forming apparatus that conveys a sheet by using oneof a plurality of conveying paths, the possibility of a conveyancemalfunction may relatively vary among the conveying paths used. If aconveyance malfunction occurs, a user needs to deal with a sheet causingthe conveyance malfunction, and this may lead to a decrease inusability. In such a situation, to reduce a conveyance malfunction, itis desired to provide a message prompting to switch the conveying path.Depending on the status of occurrence of a conveyance malfunction, amessage prompting to switch the conveying path is output.

Configuration of Image Forming Apparatus

The image forming apparatus 20 shown in FIG. 18 executes a job that is aseries of printing operation according to a printing instruction. Likereference numbers are assigned to the same components as those of theabove-described embodiments, and the description thereof is omitted.

Sheet Feeding Unit

The sheet feeding unit will be described. Sheets stacked in the sheetfeeding cassette 100 are picked up by the sheet feeding roller 102 andare conveyed to the pair of conveying rollers 104 one by one by the pairof separation rollers 103. At this time, the presence or absence ofsheets in the sheet feeding cassette 100 is detected by the sheetdetecting sensor 101. Whether a sheet is conveyed to the pair ofconveying rollers 104 is detected by the after-feeding paper presencesensor 118. The sheet fed to the pair of conveying rollers 104 isconveyed to the pair of conveying rollers 105.

At this time, one of sheets stacked in the sheet feeding cassette 100 isconveyed to the pair of conveying rollers 105 such that the uppersurface in a stacked state faces downward, and an image is formed by theimage forming unit on the lower surface in a stacked state. The sheetfeed conveying path at this time is also referred to as first sheet feedconveying path. The sheet feeding cassette 100 is also referred to asfirst sheet feeding section, and the sheet feeding roller 102 is alsoreferred to as first sheet feed conveying unit.

Subsequently, the case where a sheet is fed from a multi-purpose tray(MP tray) 140 for feeding a sheet manually as another sheet feeding unitwill be described. The MP tray 140 is an opening/closing member capableof being switched between an open position and a close position. Whenthe MP tray 140 is in the open position, the MP tray 140 serves as asheet feeding port for feeding a sheet. When the MP tray 140 is in theclose position, the MP tray 140 does not serve as a sheet feeding portfor feeding a sheet. When sheets are fed from the MP tray 140, the MPtray 140 is switched into the open position, and sheets are stacked. TheMP tray 140 is also referred to as second sheet feeding section.

When sheets are fed from the MP tray 140, the sheets stacked on the MPtray 140 are picked up by the MP sheet feeding roller 142, and areconveyed to the pair of conveying rollers 105 one by one by the pair ofMP separation rollers 143.

The presence or absence of sheets stacked on the MP tray 140 is detectedby the MP paper presence sensor 141. Sheets stacked on the MP tray 140are conveyed to the pair of conveying rollers 105 such that the uppersurface in a stacked state faces upward, and an image is formed by theimage forming unit on the upper surface in a stacked state. The sheetfeed conveying path at the time when a sheet is fed from the MP tray 140is also referred to as second sheet feed conveying path. The MP tray 140is also referred to as second sheet feeding section, and the MP sheetfeeding roller 142 is also referred to as second sheet feed conveyingunit. Furthermore, the pair of conveying rollers 105 disposed in theconveying path into which the first sheet feed conveying path and thesecond sheet feed conveying path merges and that conveys a sheet to theimage forming unit is also referred to as third sheet feed conveyingunit.

When sheets are fed from the optional sheet feeding cassette 2000 aswell, the optional sheet feeding roller 2020 picks up and feeds sheetsto the pair of optional conveying rollers 2040 one by one by means ofthe pair of optional separation rollers 2030. When sheets are fed fromthe optional sheet feeding cassette 3000 as well, the optional sheetfeeding roller 3020 picks up and feeds sheets to the pair of optionalconveying rollers 3040 one by one by means of the pair of optionalseparation rollers 3030. At this time, as in the case of the sheetfeeding cassette 100 and the MP tray 140, the presence or absence ofsheets stacked in the optional sheet feeding cassette 2000 is detectedby the sheet detecting sensor 2010, and the presence or absence ofsheets stacked in the optional sheet feeding cassette 3000 is detectedby the sheet detecting sensor 3010. Whether a sheet is conveyed to thepair of optional conveying rollers 2040 is detected by an after-feedingpaper presence sensor 2180. Whether a sheet is conveyed to the pair ofoptional conveying rollers 3040 is detected by an after-feeding paperpresence sensor 3180. The sheet fed to the pair of optional conveyingrollers 2040 is conveyed to the pair of conveying rollers 105. The sheetfed to the pair of optional conveying rollers 3040 is also conveyed tothe pair of conveying rollers 105.

As described above, components concerned with feeding of a sheet to theimage forming unit are referred to as sheet feeding unit.

Radii of Curvature of First Sheet Feed Conveying Path and Second SheetFeed Conveying Path

The first sheet feed conveying path and the second sheet feed conveyingpath have different radii of curvature. The radius of curvature of eachof the sheet feed conveying paths will be described by using theschematic cross-sectional view of the image forming apparatus of FIG.19A and examples of specific numeric values. FIG. 2A shows that the MPtray 140 is in the open state. When sheets are fed from the sheetfeeding cassette 100, a sheet is conveyed along a conveying path thatpasses through the pair of separation rollers 103 and then passesthrough the pair of conveying rollers 104. The radius of curvature ofthe conveying path is, for example, R80 (80 mm). On the other hand, whensheets are fed from the MP tray 140, a sheet is conveyed along aconveying path that passes through the pair of MP separation rollers 143and then passes through the pair of conveying rollers 105. The radius ofcurvature of the conveying path is, for example, R800 (800 mm). Here,the conveying path from the sheet feeding cassette 100 and the conveyingpath from the MP tray 140 are compared with each other by using examplesof numeric values of the radii of curvature. It is assumed that aminimum value of the radius of curvature of the conveying path in thecase where a sheet is fed from the sheet feeding cassette 100 is lessthan a minimum value of the radius of curvature of the conveying path inthe case where a sheet is fed from the MP tray 140.

For this reason, when, for example, a sheet of stiff paper, such asthick paper and envelope, is fed from the sheet feeding cassette 100, asheet passes along the conveying path with a small radius of curvature,so the conveyance resistance is large and, as a result, a conveyancemalfunction or a paper jam may occur. Accordingly, when such a sheet isfed from the MP tray 140, the sheet is not conveyed along the conveyingpath with a small radius of curvature, so a conveyance malfunction or apaper jam is reduced.

Sheet Output Section

Subsequently, sheet output sections will be described.

The image forming apparatus 20 includes the FD tray 115 to which a sheetis output face down (hereinafter, also referred to as FD output) and theFU tray 116 to which a sheet is output face up (hereinafter, alsoreferred to as FU output). The sheet output conveying path to the FDtray 115 and the sheet output conveying path to the FU tray 116 aredifferent.

The sheet output conveying path to the FD tray 115 is a conveying pathalong which a sheet is conveyed by the FU roller 111 a and the FU roller111 b, passes through the pair of FD rollers 112 and is then output tothe FD tray 115. The sheet output conveying path to the FD tray 115 isalso referred to as sheet output conveying path. When a sheet having animage on its upper surface is conveyed along the sheet output conveyingpath, the sheet is stacked on the FD tray 115 such that the surfacehaving an image faces downward (face down) (FD). The FD tray sheetoutput sensor 125 detects that a sheet is output to the FD tray 115. TheFD tray sheet output sensor 125 will be described later. The FD tray 115is also referred to as first sheet output section. The FU roller 111 aand the FU roller 111 b are also referred to as second sheet outputconveying unit, and the pair of FD rollers 112 is also referred to asfirst sheet output conveying unit.

The FU tray 116 is an opening/closing member capable of being switchedbetween an open position and a close position. When the FU tray 116 isin the close position, a sheet having an image formed by the imageforming unit is conveyed along the sheet output conveying path alongwhich the sheet is conveyed by the FU roller 111 a and the FU roller 111b and the pair of FD rollers 112 and is output to the FD tray 115. Inother words, the FU tray 116 serves as a guiding portion that guides asheet to the FD tray 115. When the FU tray 116 is in the open position,a sheet having an image formed by the image forming unit is conveyedalong the sheet output conveying path along which the sheet is conveyedby the FU roller 111 a and the FU roller 111 b and then output to the FUtray 116 without being conveyed to the pair of FD rollers 112. In otherwords, the FU tray 116 serves as not a guiding portion that guides asheet to the FD tray 115 but a sheet output tray capable of carryingsheets.

The sheet output conveying path to the FU tray 116 is a conveying pathalong which a sheet is conveyed by the FU roller 111 a and the FU roller111 b and then output to the FU tray 116. The sheet output conveyingpath to the FU tray 116 is also referred to as second sheet outputconveying path. When a sheet having an image on its upper surface isconveyed along the second sheet output conveying path, the sheet isstacked on the FU tray 116 such that the surface having an image facesupward (face up) (FU). The FU tray 116 is also referred to as secondsheet output section.

The FU tray open/close sensor 117 outputs a first signal when the FUtray 116 is in the close position, and outputs a second signal when theFU tray 116 is in the open position. The FU tray open/close sensor 117is also referred to as open/close signal output unit. The CPU 601detects the open/closed state of the FU tray 116 in accordance with thefirst signal or second signal output from the FU tray open/close sensor117. The detailed function of the FU tray open/close sensor 117 will bedescribed later.

Radii of Curvature of Sheet Output Conveying Path and Second SheetOutput Conveying Path

The sheet output conveying path and the second sheet output conveyingpath have different radii of curvature. The radius of curvature of eachof the sheet output conveying paths will be described by using theschematic cross-sectional view of the image forming apparatus of FIG. 2Band examples of specific numeric values. In FIG. 2B, the open state ofthe FU tray 116 is represented by the dashed line. When the FU tray 116is in the closed state, a sheet is conveyed along the conveying pathalong which the sheet is conveyed by the FU roller 111 a and the FUroller 111 b and the pair of FD rollers 112, and is then output to theFD tray 115, as indicated by the continuous line in FIG. 2B. The radiusof curvature of the conveying path is, for example, R75 (75 mm). On theother hand, when the FU tray 116 is in the open state, a sheet passesthrough the set of FU rollers 111, then conveyed along a conveying pathrepresented by the dashed line in FIG. 2B, and output to the FU tray116. The radius of curvature of the conveying path is, for example, R400(400 mm). Here, the conveying path to the FD tray 115 and the conveyingpath to the FU tray 116 are compared with each other by using examplesof numeric values of the radii of curvature. It is assumed that aminimum value of the radius of curvature of the sheet conveying pathformed in the case where the FU tray 116 is in the closed state is lessthan a minimum value of the radius of curvature of the sheet conveyingpath formed in the case where the FU tray 116 is in the open state.

For this reason, when, for example, a sheet of stiff paper, such asthick paper and envelope, is FD output, a sheet passes along theconveying path with a small radius of curvature in a state where heatreceived from the heater 132 remains in the sheet, so the sheet may becurled. In addition, when the radius of curvature of a conveying path issmall, the conveyance resistance is large and, as a result, a conveyancemalfunction may occur. Accordingly, when the FU tray 116 is switchedinto the open state, a sheet is not conveyed along the conveying pathwith a small radius of curvature, so a sheet conveyance malfunction isreduced.

Double-Sided Printing

Next, the case where double-sided printing is performed in the presentembodiment will be described. When the image forming apparatus 20performs printing operation to form an image on both sides of a sheet,the image forming apparatus 20 has an automatic double-sided printingmode and a manual double-sided printing mode. The automatic double-sidedprinting mode is also referred to as first double-sided printing method,and the manual double-sided printing mode is also referred to as seconddouble-sided printing method.

Automatic Double-Sided Printing Mode

When double-sided printing is performed in the automatic double-sidedprinting mode, the CPU 601 reverses the rotation of the stepping motor623 after a lapse of a predetermined time from when the trailing edge ofthe sheet having an image only on its one side passes through theafter-fixing paper presence sensor 110 in a state where the FU tray 116is closed. The predetermined time is a time calculated by the CPU 601from the conveying speed of a sheet and a distance from the after-fixingpaper presence sensor 110 to the pair of FD rollers 112. Alternatively,the CPU 601 may start the reverse rotation of the stepping motor 623after a lapse of a time calculated from the conveying speed of a sheetand the length of the sheet from when the FD tray sheet output sensor125 detects the leading edge of the sheet.

When the rotation of the stepping motor 623 is reversed, the rotation ofthe pair of FD rollers 112 is also reversed. When the rotation of thepair of FD rollers 112 is reversed, the conveying direction of the sheetis also reversed as shown in FIG. 33J. The sheet of which the conveyingdirection is reversed is conveyed from the pair of FD rollers 112 to theFU roller 111 b and an FU roller 111 c. When the sheet of which theconveying direction is reversed is conveyed to the FU roller 111 b andthe FU roller 111 c as shown in FIG. 33K, the sheet is conveyed to thedouble-sided printing conveying path L1. In the present embodiment, theFU roller 111 b also has the function of the second sheet outputconveying unit; however, the second sheet output conveying unit may bemade up of a component different from the FU roller 111 b, and the driveof the FU roller 111 b and the different component may be controlledseparately.

As shown in FIG. 33B, the conveying direction when a sheet is output tothe FD tray 115 is also referred to as first conveying direction, andthe conveying direction when the rotation of the pair of FD rollers 112is reversed and a sheet is turned around as shown in FIG. 33J is alsoreferred to as second conveying direction. In the present embodiment,the first sheet output conveying unit rotates in a first rotationaldirection and conveys a sheet in the first conveying direction in orderto convey the sheet to the FD tray 115. The first sheet output conveyingunit rotates in a second rotational direction and conveys a sheet in thesecond conveying direction in order to convey the sheet to the imageforming unit again. In this way, the first sheet output conveying unitis capable of choosing whether to convey a sheet in the first conveyingdirection by rotating in the first rotational direction or to convey asheet in the second conveying direction by rotating in the secondrotational direction.

The sheet conveyed to the double-sided printing conveying path L1 passesthrough the double-sided printing conveying sensor 113 and is conveyedto the pair of conveying rollers 105 by the pair of double-sidedprinting conveying rollers 114. When the sheet is conveyed from the pairof double-sided printing conveying rollers 114 to the pair of conveyingrollers 105, the upper surface and lower surface of the sheet are turnedupside down, and the sheet is conveyed again to the image forming unitin a state where the surface having an image faces downward. For thesheet conveyed again to the image forming unit, an image is formed onthe surface having no image, and the sheet is output to the FD tray 115.An image formed on a front surface is also referred to as first image,and an image formed on a surface having no image (also referred to asback surface) is also referred to as second image.

As described above, in the first double-sided printing method, the CPU601 causes the first sheet output conveying unit to change the conveyingdirection of a sheet having a first image only on its one side to thesecond conveying direction in a state where the FU tray 116 is closed.When the sheet having the first image only on its one side is conveyedin the second conveying direction, the sheet is conveyed to the imageforming unit again, and a second image is formed on the sheet having thefirst image only on its one side.

In this way, when double-sided printing is performed with the firstdouble-sided printing method, the CPU 601 feeds a sheet from the sheetfeeding cassette 100 and outputs the sheet to the FD tray 115. In otherwords, a sheet is conveyed along the first sheet feed conveying pathwith a smaller radius of curvature than the second sheet feed conveyingpath, and the sheet output conveying path with a smaller radius ofcurvature than the second sheet output conveying path. For this reason,when, for example, a sheet of stiff paper, such as thick paper andenvelope, is FD output, a sheet passes along the conveying path with asmall radius of curvature in a state where heat received from the heater132 remains in the sheet, so the sheet may be curled. In addition, whenthe radius of curvature of a conveying path is small, the conveyanceresistance is large and, as a result, a conveyance malfunction mayoccur. Accordingly, when the sheet feeding section is switched from thesheet feeding cassette 100 to the MP tray 140 and the FU tray 116 isswitched into the open state, a sheet conveyance malfunction is reducedrather than a sheet is conveyed along the conveying path with a smallradius of curvature. This double-sided printing method is also referredto as manual double-sided printing mode.

Manual Double-Sided Printing Mode

When double-sided printing is performed in the manual double-sidedprinting mode, the sheet feeding section is switched to the MP tray 140.When printing is started in a state where the FU tray 116 is open, asheet having a first image on its one side is output to the FU tray 116.

Subsequently, a user needs to perform operation as will be describedbelow. In the present embodiment, the message shown in FIG. 37H may beoutput by the message output unit.

Initially, a user sets a sheet on the MP tray 140 such that the surface,having an image, of a sheet having an image on its one side and outputto the FU tray 116 faces downward. When the sheet having an image on itsone side is set on the MP tray 140 by the user, the CPU 601 resumes thesuspended printing operation. The sheet set on the MP tray 140 by theuser is conveyed again to the image forming unit by the MP sheet feedingroller 142. For the sheet conveyed again to the image forming unit, atoner image is formed on the surface having no image and fixed, and thenthe sheet is output to the FU tray 116.

As described above, in the second double-sided printing method, the CPU601 causes the sheet having a first image only on its one side to beoutput to the second sheet output section. When the sheet output to thesecond sheet output section is stacked on the sheet feeding unit, theCPU 601 causes the sheet feeding unit to convey the sheet to the imageforming unit again and causes the image forming unit to form a secondimage on the sheet having the first image only on its one side.

In the present embodiment, a double-sided printing method that iscapable of eventually forming an image on both sides of a sheet withoutusing the double-sided printing conveying path L1 is referred to asmanual double-sided printing mode.

Message Output Unit

The operation panel 626 is provided at the top of the image formingapparatus 20. The operation panel 626 is made up of a liquid crystalpanel and a keypad. The liquid crystal panel provides information, suchas instruction details to a user, by displaying an image and/or text.The keypad receives instructions from the user. In the presentembodiment, the operation panel 626 is also referred to as messageoutput unit that outputs information for providing a message to a user.

Configuration of Printer Control System

FIG. 19A is a block diagram that illustrates the configuration of awhole printer control system of the present embodiment. Like referencenumerals are assigned to the same components described with reference toFIG. 3A, and the description thereof is omitted.

FIG. 19B is a block diagram showing the configuration of hardwareconcerned with sheet conveyance control as a software functionimplemented by the printing section 221 of the present embodiment. Likereference numerals are assigned to the same components described withreference to FIG. 3B, and the description thereof is omitted.

The CPU 601 communicates with the ROM 603, the RAM 604, an NVRAM 608,the I/O port 606, and the serial communication port 607 via thecommunication bus 605. The CPU 601 controls the printing section 221 byexecuting a computer program stored in the ROM 603, the RAM 604, and theNVRAM 608. The CPU 601 executes a program stored in the ROM 603,acquires a calculated result during execution, and saves the calculatedresult in the RAM 604. Alternatively, the CPU 601 and an MPU (not shown)including a plurality of processors, such as multi-cores, may controlthe printing section 221 with the plurality of processors.

One or more memories such as the ROM 603 and the RAM 604 store variouspieces of information including a computer program for performingvarious operations (described later), communication parameters forwireless communication, and the like. The one or more memories such asthe ROM 603 and the RAM 604 may be, for example, a storage medium, suchas a flexible disk, a hard disk drive, an optical disk, amagneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatilememory card, and a DVD.

The NVRAM 608 is a non-volatile random access memory and is capable ofstoring information detected by the CPU 601. Hereinafter, the CPU 601 isalso referred to as control unit, and the NVRAM 608 is also referred toas storage unit.

Method with which CPU 601 Detects Conveyance Malfunction

Next, in the present embodiment, how the CPU 601 acquires informationabout a conveyance malfunction when a conveyance malfunction hasoccurred will be described. The image forming apparatus 20 in thepresent embodiment is capable of detecting a conveyance malfunction atvarious locations in the conveying path. Among the various locations,three cases will be described.

Sheet Output Conveyance Malfunction (First Detection Method)

Hereinafter, a detection method with which the CPU 601 detects that asheet output conveyance malfunction has occurred in the sheet outputconveying path will be described.

Initially, the case where the FU tray 116 is in the close position and asheet is conveyed normally will be described. When a sheet is conveyednormally, after a lapse of a predetermined time from when the leadingedge of the sheet is detected by the after-fixing paper presence sensor110 as shown in FIG. 33A, the sheet is not detected by the after-fixingpaper presence sensor 110 as shown in FIG. 33B.

The predetermined time in this case is a time calculated by using thelength of a sheet fed by the sheet feeding unit and the conveying speedof the sheet. The length of a sheet here may be defined according to atype of sheet selected by a user at the host computer 200 or may be setto the length of a longest sheet that can be printed by the imageforming apparatus 20. Alternatively, the length of a sheet here may beset to the length of a sheet measured by the CPU 601 using theregistration sensor 106 at the time when the sheet passes through theregistration sensor 106.

When the FU tray 116 is in the close position and a conveyancemalfunction occurs, the state is as shown in FIG. 33C. In other words,even after a lapse of a predetermined time from when the leading edge ofa sheet is detected by the after-fixing paper presence sensor 110, thesheet is continuously detected by the after-fixing paper presence sensor110. At this time, the CPU 601 initially receives a LOW signal outputfrom the FU tray open/close sensor 117. In addition, the CPU 601receives a LOW signal output from the after-fixing paper presence sensor110 after a lapse of a predetermined time from when the LOW signaloutput from the after-fixing paper presence sensor 110 is received. Whenthe CPU 601 has received these signals, the CPU 601 detects that a sheetoutput conveyance malfunction has occurred. In the present embodiment,the method of detecting a sheet output conveyance malfunction is alsoreferred to as first detection method.

When the FU tray 116 is in the close position, a small-size sheet, suchas an A5 sheet and an A6 sheet, is conveyed by the FU roller 111 a andthe FU roller 111 b and then placed in a state where the sheet is notdetected by any paper presence sensor as shown in FIG. 33D. In thiscase, the CPU 601 initially receives a LOW signal output from the FUtray open/close sensor 117. In addition, the CPU 601 receives a HIGHsignal output from the after-fixing paper presence sensor 110 after alapse of a predetermined time from when a LOW signal output from theafter-fixing paper presence sensor 110 is received. When the CPU 601 hasreceived these signals, the CPU 601 detects that a paper jam hasoccurred.

Sheet Output Conveyance Malfunction (Second Detection Method)

The CPU 601 may detect a sheet output conveyance malfunction with amethod different from the above. Initially, the case where the FU tray116 is in the close position and a sheet is conveyed normally will bedescribed. When a sheet is conveyed normally, after a lapse of apredetermined time from when the leading edge of the sheet is detectedby the after-fixing paper presence sensor 110 as shown in FIG. 33A, theleading edge of the sheet is detected by the FD tray sheet output sensor125 as shown in FIG. 33E. The predetermined time in this case is a timecalculated by using the length of the conveying path from theafter-fixing paper presence sensor 110 to the FD tray sheet outputsensor 125 and the conveying speed of the sheet.

When the FU tray 116 is in the close position and a conveyancemalfunction occurs, the state is as shown in FIG. 33F. In other words,even after a lapse of a predetermined time from when the leading edge ofa sheet is detected by the after-fixing paper presence sensor 110, thesheet is not detected by the FD tray sheet output sensor 125. At thistime, the CPU 601 initially receives a LOW signal output from the FUtray open/close sensor 117. In addition, the CPU 601 receives a HIGHsignal output from the FD tray sheet output sensor 125 after a lapse ofa predetermined time from when the LOW signal output from theafter-fixing paper presence sensor 110 is received. When the CPU 601 hasreceived these signals, the CPU 601 may detect that a sheet outputconveyance malfunction has occurred. In the present embodiment, themethod of detecting a sheet output conveyance malfunction is alsoreferred to as second detection method.

Sheet Feed Conveyance Malfunction

Hereinafter, a detection method with which the CPU 601 detects that asheet feed conveyance malfunction has occurred in the sheet feedconveying path will be described.

Initially, the sheet feeding roller 102 starts feeding a sheet. When asheet is conveyed normally, the sheet is not detected by theafter-feeding paper presence sensor 118 as shown in FIG. 33H after alapse of a predetermined time from when the leading edge of the sheet isdetected by the after-feeding paper presence sensor 118 as shown in FIG.33G.

The predetermined time in this case is a time calculated by using thelength of a sheet and the conveying speed of the sheet. The length of asheet here may be defined according to a type of sheet selected by auser at the host computer 200 or may be set to the length of a longestsheet that can be printed by the image forming apparatus 20.Alternatively, the length of a sheet here may be set to the length of asheet measured by the CPU 601 using the after-feeding paper presencesensor 118 at the time when the sheet passes through the after-feedingpaper presence sensor 118.

When a conveyance malfunction occurs, the state is as shown in FIG. 33I.In other words, even after a lapse of a predetermined time from when theleading edge of a sheet is detected by the after-feeding paper presencesensor 118, the sheet is continuously detected by the after-feedingpaper presence sensor 118. At this time, when the CPU 601 receives a LOWsignal output from the after-feeding paper presence sensor 118 after alapse of a predetermined time from when the LOW signal output from theafter-feeding paper presence sensor 118 is received, the CPU 601 detectsthat a sheet feed conveyance malfunction has occurred. A LOW signal anda HIGH signal output from the after-feeding paper presence sensor 118are also respectively referred to as third signal and fourth signal.

Double-Sided Printing Conveyance Malfunction

Hereinafter, a detection method with which the CPU 601 detects that adouble-sided printing conveyance malfunction has occurred in thedouble-sided printing conveying path will be described.

This is the case where, after a sheet having a first image is conveyedby the pair of FD rollers 112, a conveyance malfunction occurs beforethe sheet is conveyed to the image forming unit again.

Initially, when the FU tray 116 is in the close position and a sheet isconveyed normally, the pair of FD rollers 112 starts reverse rotation bychanging the rotational direction from the first rotational direction tothe second rotational direction as shown in FIG. 33J, and the sheet isconveyed in the second conveying direction changed from the firstconveying direction. Subsequently, as shown in FIG. 33K, the sheet isconveyed to the double-sided printing conveying path L1. After the pairof FD rollers 112 starts reverse rotation in the second rotationaldirection, when a predetermined time has elapsed from when the sheetbegins to be conveyed in the second conveying direction, the leadingedge of the sheet is detected by the registration sensor 106 as shown inFIG. 33L. The predetermined time in this case is a time calculated byusing the length of the conveying path from the pair of FD rollers 112to the registration sensor 106 via the FU roller 111 b and the FU roller111 c, and the conveying speed of a sheet.

However, if a conveyance malfunction occurs, the state is as shown inFIG. 33M, and, even when a predetermined time elapses from when the pairof FD rollers 112 starts reverse rotation and the sheet begins to beconveyed in the second conveying direction, the leading edge of thesheet is not detected by the registration sensor 106. In other words,even after a lapse of a predetermined time from when the stepping motor623 starts reverse rotation, a HIGH signal is continuously output fromthe registration sensor 106. At this time, the CPU 601 initiallyreceives a LOW signal output from the FU tray open/close sensor 117. Inaddition, after a lapse of a predetermined time from when the steppingmotor 623 starts reverse rotation, the CPU 601 receives a HIGH signaloutput from the registration sensor 106. When the CPU 601 has receivedthese signals, the CPU 601 detects that a double-sided printingconveyance malfunction has occurred. A LOW signal and a HIGH signaloutput from the registration sensor 106 are also respectively referredto as fifth signal and sixth signal.

Method of Storing Information about Conveyance Malfunction

When the CPU 601 detects the above-described conveyance malfunctionsduring execution of a job, the CPU 601 causes the NVRAM 608 to storeinformation about the conveyance malfunctions. At this time, the CPU 601causes the NVRAM 608 to store information about a conveyance malfunctionby using, for example, a flag of “0” or “1”.

The CPU 601 may cause the NVRAM 608 to store information for outputtinga message as follows on the operation panel 626 when the CPU 601 detectsa conveyance malfunction during execution of a job. The message in thiscase is a message prompting to switch the conveying path to reduce aconveyance malfunction or a message informing a user that there is apossibility that a conveyance malfunction occurs or there is a historythat a conveyance malfunction has occurred. The CPU 601 is capable ofprompting a user to perform operation for avoiding a conveyancemalfunction by outputting the message on the operation panel 626, so itis possible to reduce occurrence of a conveyance malfunction again.

Since the NVRAM 608 is a non-volatile memory, even when the power of theimage forming apparatus 20 is turned off after a lapse of apredetermined time from when a job causing a conveyance malfunctioncompletes, a state where information about the conveyance malfunction isstored in the NVRAM 608 is maintained. Therefore, even when a first jobfor a first printing instruction completes and then a second job for asecond printing instruction is executed after a lapse of a predeterminedtime, the CPU 601 outputs the message as described above on theoperation panel 626. By outputting the message as described above, it ispossible to reduce occurrence of a conveyance malfunction again. Themessage as described above is output before a sheet on which the lastimage in the second job is to be formed is fed or before the last imagein the second job is formed.

In addition, the CPU 601 may cause the NVRAM 608 to store the number oftimes a conveyance malfunction has occurred and, when a conveyancemalfunction has occurred a predetermined number of times, cause theNVRAM 608 to store information about occurrence of a conveyancemalfunction. The predetermined number of times here is the number oftimes at or above which the possibility of occurrence of a conveyancemalfunction relatively increases and is, for example, the case where aconveyance malfunction has occurred five times or more out of recent 10times of sheet feeding. A user may be allowed to change the setting ofthe predetermined number of times with the operation panel 626.

In addition, the CPU 601 may delete information about detection of asheet output conveyance malfunction from the NVRAM 608 when a sheetoutput conveyance malfunction has not occurred in a predeterminedconsecutive number of sheets and a printing operation has been completednormally. The predetermined number of sheets here is, for example, 10sheets and, when 10 sheets are consecutively normally conveyed, it isdetermined that the possibility of occurrence of a conveyancemalfunction has decreased. A user may be allowed to change the settingof the predetermined number of sheets with the operation panel 626.

Hereinafter, a specific process for reducing occurrence of each of threeconveyance malfunctions will be described.

Process for Reducing Sheet Output Conveyance Malfunction

In the present embodiment, when a sheet output conveyance malfunctionhas occurred, there is a possibility that the same conveyancemalfunction occurs again. In this case, by prompting a user to switchthe FU tray 116 into the open position, occurrence of the sameconveyance malfunction again is reduced. A sheet output conveyancemalfunction is as described in Sheet Output Conveyance Malfunction(First Detection Method).

A specific process in the case where there is a possibility that a sheetoutput conveyance malfunction occurs and in the case where a sheetoutput conveyance malfunction has occurred will be described withreference to the flowcharts of FIG. 34A and FIG. 34B. The flowcharts ofFIG. 34C and FIG. 34D are a modification of FIG. 34A and FIG. 34B. Likestep numbers are assigned to the same steps, and the description thereofis omitted.

Initially, the CPU 601 receives, from the printer controller 213, aprinting instruction including information about a series of printingoperation to cause the sheet feeding unit to feed a sheet and cause theimage forming unit to form an image on the sheet and output the sheet.The CPU 601 starts a job in accordance with the printing instruction.

In S5101, when information about occurrence of a sheet output conveyancemalfunction is stored in the NVRAM 608, the CPU 601 advances the processto S5102. In S5101, when information about occurrence of a sheet outputconveyance malfunction is not stored in the NVRAM 608, the CPU 601starts the printing operation in a state where the FU tray 116 isclosed, and the process proceeds to S5104.

In S5102, the CPU 601 outputs, to the operation panel 626, a messageprompting to switch into the position in which the FU tray 116 is open.A message to be output at this time may be, for example, the sentenceshown in FIG. 37A or may be, for example, the picture shown in FIG. 37B.Alternatively, in order for a user to easily understand necessaryoperation, for example, the picture shown in FIG. 37B may be animatedand displayed on the operation panel 626.

The message output to the operation panel 626 in S5102 may be a messageinforming a user that there is a possibility of occurrence of aconveyance malfunction or there is a history that a conveyancemalfunction has occurred. By outputting this message, a user switchesthe FU tray 116 into the open position in response to the message outputto the operation panel 626. By prompting this operation, it is possibleto reduce occurrence of a conveyance malfunction, and this leads toimprovement in usability.

In S5103, OK button contained in the message prompting to switch the FUtray 116 into the open position is depressed by the user. When the CPU601 acquires information indicating that OK button contained in themessage prompting to switch the FU tray 116 into the open position hasbeen depressed, the process proceeds to S5104.

In S5104, the leading edge of a sheet having an image formed by theimage forming unit passes through the after-fixing paper presence sensor110 as shown in FIG. 33A, and a HIGH signal to be output to the CPU 601by the after-fixing paper presence sensor 110 switches to a LOW signal.When the CPU 601 receives a LOW signal output from the after-fixingpaper presence sensor 110, the process proceeds to S5105.

In S5105, the CPU 601 determines whether a predetermined time haselapsed. The predetermined time in this case is a time calculated byusing the length of a sheet fed by the sheet feeding unit and theconveying speed of the sheet. As the predetermined time elapses, the CPU601 advances the process to S5106. The process in S5106 and thefollowing steps vary depending on whether a conveyance malfunction hasoccurred.

When a sheet is conveyed normally, the state is shown in FIG. 33B. Inother words, in S5106, a sheet is detected by the FD tray sheet outputsensor 125, the CPU 601 receives a LOW signal output by the FD traysheet output sensor 125, and then the process proceeds to S5107. InS5107, when a sheet is output to the FD tray 115, the process proceedsto S5115.

When the FU tray 116 is in the open position and a sheet is conveyednormally, the sheet is not detected by the FD tray sheet output sensor125 in S5106. For this reason, the CPU 601 receives a HIGH signal outputfrom the FD tray sheet output sensor 125, and the process proceeds toS5108. In S5108, a sheet is not detected by the after-fixing paperpresence sensor 110, and the CPU 601 receives a HIGH signal output fromthe after-fixing paper presence sensor 110, and the process proceeds toS5109. In S5109, when the FU tray 116 is in the open position and theCPU 601 receives a HIGH signal output from the FU tray open/close sensor117, the process proceeds to S5110. In S5110, when a sheet is output tothe FU tray 116, the process proceeds to S5115.

When a conveyance malfunction has occurred, the state is shown in FIG.33C. In other words, in S5106, the sheet is not detected by the FD traysheet output sensor 125, the CPU 601 receives a HIGH signal output fromthe FD tray sheet output sensor 125, and the process proceeds to S5108.In S5108, the sheet is continuously detected by the after-fixing paperpresence sensor 110, and the CPU 601 receives a LOW signal output fromthe after-fixing paper presence sensor 110, and the process proceeds toS5111.

When a sheet having a size, such as A5 size and A6 size, is conveyed, itbecomes like a state where a paper jam has occurred, and the state isshown in FIG. 33D. In other words, in S5106, the sheet is not detectedby the FD tray sheet output sensor 125, the CPU 601 receives a HIGHsignal output from the FD tray sheet output sensor 125, and the processproceeds to S5108. In S5108, the sheet is not detected by theafter-fixing paper presence sensor 110, the CPU 601 receives a HIGHsignal output from the after-fixing paper presence sensor 110, theprocess proceeds to S5109. In S5109, when the FU tray 116 is in theclose position and the CPU 601 receives a LOW signal output from the FUtray open/close sensor 117, the process proceeds to S5111.

In S5111, the CPU 601 detects that a sheet output conveyance malfunctionhas occurred and causes the NVRAM 608 to store information aboutoccurrence of a sheet output conveyance malfunction, and the processproceeds to S5112.

In S5112, the CPU 601 outputs, to the operation panel 626, a messageprompting to remove the sheet in a conveyance malfunction. A message tobe output at this time may be, for example, the sentence shown in FIG.37I or may be a picture. Alternatively, in order for a user to easilyunderstand necessary operation, an animation may be displayed on theoperation panel 626. A sheet in a sheet output conveyance malfunction isalso referred to as first sheet.

In S5113, when the sheet in a conveyance malfunction is removed by theuser, the CPU 601 receives a HIGH signal output from the after-fixingpaper presence sensor 110, and the process proceeds to S5114.

In S5114, when the FU tray 116 is switched into the close position bythe user, the CPU 601 receives a LOW signal output from the FU trayopen/close sensor 117, and the process proceeds to S5115.

In the present embodiment, when the CPU 601 completes the processes ofS5113 and S5114, the CPU 601 detects that jam recovery is complete. Whenthe CPU 601 detects that jam recovery is complete, the CPU 601 starts aprocess of reforming the image formed on the sheet in a conveyancemalfunction onto a new sheet. This process is referred to as reprint. Anew sheet is also referred to as second sheet.

In S5115, when reprint is performed, the CPU 601 returns the process toS5101 and starts a process of reforming the image formed on the sheet ina conveyance malfunction onto a new sheet.

In S5115, when the sheet is normally output up to the process of S5107or S5110 but the job is not complete, and the CPU 601 has receivedinformation to perform image formation again from the printer controller213, the process returns to S5101. When the job is complete and theimage is not formed again, the CPU 601 ends the process.

In the present embodiment, the CPU 601 may advance the process to S5116after S5107 as shown in FIG. 34C and FIG. 34D.

In S5116, when a sheet is normally output to the FD tray 115 andinformation about the fact that a LOW signal output from the FD traysheet output sensor 125 is detected a predetermined number of times isstored in the NVRAM 608, the CPU 601 advances the process to S5117.

In S5117, when information about the fact that a sheet output conveyancemalfunction is detected is stored in the NVRAM 608, the CPU 601 deletes,from the NVRAM 608, information about the fact that a sheet outputconveyance malfunction has occurred, and the process proceeds to S5115.

By executing the processes of S5116 and S5117, it is possible to outputa message to the user in S5102 only just after occurrence of aconveyance malfunction and there is a high possibility that a conveyancemalfunction occurs again, and this leads to improvement in usability.

In this flowchart, the case where a sheet output conveyance malfunctionis detected with the first detection method has been described.Alternatively, a sheet output conveyance malfunction may be detectedwith the second detection method.

As described above, the CPU 601 is capable of reducing occurrence of asheet output conveyance malfunction again by outputting a messageprompting to switch the FU tray 116 into the open position.

Process for Reducing Sheet Feed Conveyance Malfunction

In the present embodiment, when a sheet feed conveyance malfunctionoccurs, there is a possibility that the same conveyance malfunctionoccurs again. In this case, by prompting a user to switch the sheetfeeding unit from the sheet feeding cassette 100 to the MP tray 140,occurrence of the same conveyance malfunction again is reduced. A sheetfeed conveyance malfunction is as described in Sheet Feed ConveyanceMalfunction.

A specific process in the case where there is a possibility that a sheetfeed conveyance malfunction occurs and in the case where a sheet feedconveyance malfunction has occurred will be described with reference tothe flowcharts of FIG. 35A and FIG. 35B. The flowcharts of FIG. 35C andFIG. 35D are a modification of FIG. 35A and FIG. 35B. Like step numbersare assigned to the same steps, and the description thereof is omitted.

Initially, the CPU 601 receives, from the printer controller 213, aprinting instruction including information about a series of printingoperation to cause the sheet feeding unit to feed a sheet and cause theimage forming unit to form an image on the sheet and output the sheet.The CPU 601 starts a job in accordance with the printing instruction.

In S5201, when information about occurrence of a sheet feed conveyancemalfunction is stored in the NVRAM 608, the CPU 601 advances the processto S5202. When information about the fact that occurrence of a sheetfeed conveyance malfunction is detected is not stored in the NVRAM 608,the process proceeds to S5205.

In S5202, the CPU 601 switches the sheet feeding unit from the sheetfeeding cassette 100 to the MP tray 140 and outputs, to the operationpanel 626, a message prompting to stack a sheet on the MP tray 140. Amessage to be output at this time may be, for example, the sentenceshown in FIG. 37C or may be, for example, the picture shown in FIG. 37D.Alternatively, in order for a user to easily understand necessaryoperation, for example, the picture shown in FIG. 37D may be animatedand displayed on the operation panel 626.

The message output to the operation panel 626 in S5202 may be a messageinforming a user that there is a possibility of occurrence of aconveyance malfunction or there is a history that a conveyancemalfunction has occurred. By outputting this message, the user switchesthe sheet feeding unit from the sheet feeding cassette 100 to the MPtray 140 and stack a sheet on the MP tray 140 in response to the messageoutput to the operation panel 626. By prompting this operation, it ispossible to reduce occurrence of a conveyance malfunction, and thisleads to improvement in usability.

In S5203, OK button contained in the message prompting to stack a sheeton the MP tray 140 is depressed by the user. When the CPU 601 acquiresinformation indicating that OK button contained in the message promptingto stack a sheet on the MP tray 140 has been depressed, the processproceeds to S5204.

In S5204, when a sheet is stacked on the MP tray 140 and the CPU 601receives a LOW signal output from the MP paper presence sensor 141, theprocess proceeds to S5208. When a sheet is not stacked on the MP tray140 and the CPU 601 receives a HIGH signal output from the MP paperpresence sensor 141, the process proceeds to S5205.

In S5205, the sheet feeding cassette solenoid 625 that drives the sheetfeeding roller 102 begins to drive the sheet feeding roller 102, and asheet is fed as shown in FIG. 33D. When the CPU 601 acquires informationindicating that the sheet feeding cassette solenoid 625 begins to drive,the process proceeds to S5206.

In S5206, the CPU 601 determines whether a predetermined time haselapsed. The predetermined time in this case is a time calculated byusing the length of a sheet fed by the sheet feeding unit and theconveying speed of the sheet. As the predetermined time elapses, the CPU601 advances the process to S5207. The process in S5207 and thefollowing steps vary depending on whether a conveyance malfunction hasoccurred.

When a sheet is conveyed normally, the state is shown in FIG. 33H. Inother words, in S5207, a sheet is not detected by the after-feedingpaper presence sensor 118, the CPU 601 receives a HIGH signal outputfrom the after-feeding paper presence sensor 118, and the processproceeds to S5208. In S5208, the sheet is conveyed to the image formingunit, the sheet having an image is output to the FD tray 115 or the FUtray 116, and the process proceeds to S5213.

When a conveyance malfunction has occurred, the state is shown in FIG.33I. In other words, in S5207, a sheet is continuously detected by theafter-feeding paper presence sensor 118, the CPU 601 receives a LOWsignal output from the after-feeding paper presence sensor 118, and theprocess proceeds to S5209.

In S5209, the CPU 601 detects that a sheet feed conveyance malfunctionhas occurred, and causes the NVRAM 608 to store information aboutoccurrence of a sheet feed conveyance malfunction, and then the processproceeds to S5210.

In S5210, the CPU 601 outputs, to the operation panel 626, a messageprompting to remove the sheet in a conveyance malfunction. A message tobe output at this time may be, for example, the sentence shown in FIG.37I or may be a picture. Alternatively, in order for a user to easilyunderstand necessary operation, an animation may be displayed on theoperation panel 626. A sheet placed in a sheet feed conveyancemalfunction is also referred to as third sheet.

In S5211, when the sheet in a conveyance malfunction is removed by theuser, the CPU 601 receives a HIGH signal output from the after-feedingpaper presence sensor 118, and the process proceeds to S5212.

In S5212, a door (not shown) of the image forming apparatus 20, openedby the user to remove the sheet in a conveyance malfunction, is switchedinto the close position. When the door (not shown) of the image formingapparatus 20 is switched into the close position, the CPU 601 receives aLOW signal output from an open/close sensor for the door (not shown),and the process proceeds to S5213.

In the present embodiment, when the CPU 601 completes the processes ofS5211 and S5212, the CPU 601 detects that jam recovery is complete. Whenthe CPU 601 detects that jam recovery is complete, the CPU 601 starts aprocess of reforming the image formed on the sheet in a conveyancemalfunction onto a new sheet. This process is referred to as reprint. Anew sheet is also referred to as second sheet.

In S5213, when reprint is performed, the CPU 601 returns the process toS5201 and starts a process of reforming the image formed on the sheet ina conveyance malfunction onto a new sheet. At this time, a sheet in aconveyance malfunction is also referred to as third sheet, and a newsheet is also referred to as fourth sheet.

In S5213, when a sheet is normally conveyed during the process of S5208but the job is not complete, and the CPU 601 has received information toperform image formation again from the printer controller 213, theprocess returns to S5201. When the job is complete and the image is notformed again, the CPU 601 ends the process.

A printing instruction in a job in the case where a sheet feedconveyance malfunction has occurred is also referred to as thirdprinting instruction, and a job in the case where a sheet feedconveyance malfunction has occurred is also referred to as third job. Aprinting instruction that the CPU 601 newly receives from the printercontroller 213 after a sheet feed conveyance malfunction is resolved isalso referred to as fourth printing instruction, and a job that the CPU601 executes in accordance with a printing instruction newly receivedfrom the printer controller 213 is also referred to as fourth job.

In the present embodiment, the CPU 601 may advance the process to S5214after S5208 as shown in FIG. 35C and FIG. 35D.

In S5214, when a sheet is normally conveyed to the image forming unitand information about the fact that a LOW signal output from theregistration sensor 106 is detected a predetermined number of times isstored in the NVRAM 608, the CPU 601 advances the process to S5215.

In S5215, when information about the fact that a sheet feed conveyancemalfunction is detected is stored in the NVRAM 608, the CPU 601 deletes,from the NVRAM 608, information about the fact that a sheet feedconveyance malfunction has occurred, and the process proceeds to S5213.

By executing the processes of S5214 and S5215, it is possible to outputa message to the user in S5202 only just after occurrence of aconveyance malfunction and there is a high possibility that a conveyancemalfunction occurs, and this leads to improvement in usability.

As described above, the CPU 601 switches the sheet feeding unit from thesheet feeding cassette 100 to the MP tray 140 and outputs a messageprompting to stack a sheet on the MP tray 140. By outputting themessage, it is possible to reduce occurrence of a sheet feed conveyancemalfunction again.

Process for Reducing Double-Sided Printing Conveyance Malfunction

In the present embodiment, when a double-sided printing conveyancemalfunction has occurred, there is a possibility that the sameconveyance malfunction occurs again. In this case, by prompting toswitch the FU tray 116 into the open position and to switch the sheetfeeding unit from the sheet feeding cassette 100 to the MP tray 140,occurrence of the same conveyance malfunction again is reduced. Adouble-sided printing conveyance malfunction is as described inDouble-Sided Printing Conveyance Malfunction.

A specific process in the case where there is a possibility that adouble-sided printing conveyance malfunction occurs and in the casewhere a double-sided printing conveyance malfunction has occurred willbe described with reference to the flowcharts of FIG. 36A and FIG. 36B.The flowcharts of FIG. 36C and FIG. 36D are a modification of FIG. 36Aand FIG. 36B. Like step numbers are assigned to the same steps, and thedescription thereof is omitted.

As an example of double-sided printing operation, the case where aseries of operation in which, after the conveying direction of a sheethaving a first image only on its one side is switched by the pair of FDrollers 112 to the second conveying direction, the sheet is conveyedagain to the image forming unit and then the image forming unit iscaused to form a second image on the sheet will be described.

Initially, the CPU 601 receives, from the printer controller 213, aprinting instruction including information on a series of double-sidedprinting operation. The CPU 601 starts a job in accordance with theprinting instruction.

In S5301, when information about occurrence of a double-sided printingconveyance malfunction is stored in the NVRAM 608, the CPU 601 advancesthe process to S5302. In S5301, when information about occurrence of adouble-sided printing conveyance malfunction is not stored in the NVRAM608, the CPU 601 starts the printing operation in a state where the FUtray 116 is closed, and the process proceeds to S5307.

In S5302, the CPU 601 switches the FU tray 116 into the open positionand outputs, to the operation panel 626, a message prompting to switchthe sheet feeding unit from the sheet feeding cassette 100 to the MPtray 140. A message to be output at this time may be, for example, thesentence shown in FIG. 37G or may be, for example, the picture shown inFIG. 37B or FIG. 37F. Alternatively, in order for a user to easilyunderstand necessary operation, for example, the picture shown in FIG.37B or FIG. 37F may be animated and displayed on the operation panel626.

The message output to the operation panel 626 in S5302 may be a messageinforming a user that there is a possibility of occurrence of aconveyance malfunction or there is a history that a conveyancemalfunction has occurred. By outputting this message, the user switchesthe FU tray 116 into the open position and switches the sheet feedingunit from the sheet feeding cassette 100 to the MP tray 140 in responseto the message output to the operation panel 626. By prompting thisoperation, it is possible to reduce occurrence of a conveyancemalfunction, and this leads to improvement in usability.

In S5303, OK button contained in the message prompting the user toswitch the FU tray 116 into the open position and to switch the sheetfeeding unit from the sheet feeding cassette 100 to the MP tray 140 isdepressed. When the CPU 601 acquires information indicating that OKbutton contained in the message prompting to switch the FU tray 116 intothe open position and to switch the sheet feeding unit from the sheetfeeding cassette 100 to the MP tray 140 has been depressed, the processproceeds to S5304.

In S5304, when the sheet is stacked on the MP tray 140 and the CPU 601receives a LOW signal output from the MP paper presence sensor 141, theprocess proceeds to S5305. When a sheet is not stacked on the MP tray140 and the CPU 601 has not received a LOW signal output from the MPpaper presence sensor 141, the process proceeds to S5306.

In S5305, the sheet is fed from the MP tray 140, and the processproceeds to S5307.

In S5306, the sheet is fed from the sheet feeding cassette 100, and theprocess proceeds to S5307.

In S5307, when the leading edge of the sheet passes through theregistration sensor 106, the registration sensor 106 outputs a LOWsignal to the CPU 601. When the CPU 601 receives a LOW signal outputfrom the registration sensor 106, the process proceeds to S5308.

In S5308, the sheet is conveyed to the image forming unit, a first imageis formed by the image forming unit, and the process proceeds to S5309.

In S5309, when the FU tray 116 is in the open position and the CPU 601receives a HIGH signal output from the FU tray open/close sensor 117,the process proceeds to S5314. When the FU tray 116 is in the closeposition and the CPU 601 receives a LOW signal output from the FU trayopen/close sensor 117, the process proceeds to S5310. First, the processin S5314 and the following steps will be described.

In S5314, when the sheet on which the first image is formed by the imageforming unit is output to the FU tray 116, the process proceeds toS5315.

In S5315, the CPU 601 outputs, to the operation panel 626, a messageprompting to stack the sheet having the first image only on its one sideonto the MP tray 140, and the process proceeds to S5316. The messageoutput at this time may be, for example, the message shown in FIG. 37H.Alternatively, in order for a user to easily understand necessaryoperation, for example, the picture in the message shown in FIG. 37H maybe animated and displayed on the operation panel 626.

In S5316, when OK button contained in the message output in S5315 isdepressed by the user and the CPU 601 acquires information indicatingthat OK button has been depressed, the process proceeds to S5317.

In S5317, when the sheet is stacked on the MP tray 140 and the CPU 601receives a LOW signal output from the MP paper presence sensor 141, theprocess proceeds to S5318. When the sheet is not stacked on the MP tray140 and the CPU 601 has not received a LOW signal output from the MPpaper presence sensor 141, the process returns to S5315.

In S5318, when the sheet having the first image only on its one side isconveyed to the image forming unit, a second image is formed on thesheet by the image forming unit, and the sheet is output to the FU tray116, the process proceeds to S5323.

Subsequently, the process in S5310 and the following steps will bedescribed. In S5310, the stepping motor 623 starts reverse rotation, thepair of FD rollers 112 rotates in the reverse direction, and the sheetbegins to be conveyed in the second conveying direction. When the CPU601 receives information indicating that the stepping motor 623 beginsto rotate in the reverse direction, the process proceeds to S5311.

In S5311, the CPU 601 determines whether a predetermined time haselapsed. The predetermined time in this case is s time calculated byusing the conveying speed of a sheet and a distance from the pair of FDrollers 112 to the registration sensor 106. As the predetermined timeelapses, the CPU 601 advances the process to S5312. The process in S5312and the following steps vary depending on whether a conveyancemalfunction has occurred.

When a sheet is conveyed normally, the state is shown in FIG. 33L. Inother words, in S5312, the sheet is detected by the registration sensor106, the CPU 601 receives a LOW signal output from the registrationsensor 106, and the process proceeds to S5313. In S5313, when the sheetis output to the FD tray 115, the process proceeds to S5323.

When a conveyance malfunction has occurred, the state is shown in FIG.33M. In other words, in S5312, the sheet is not detected by theregistration sensor 106, the CPU 601 receives a HIGH signal output fromthe registration sensor 106, and the process proceeds to S5319.

In S5319, the CPU 601 detects that a double-sided printing conveyancemalfunction has occurred and causes the NVRAM 608 to store informationabout occurrence of a double-sided printing conveyance malfunction, andthe process proceeds to S5320.

In S5320, the CPU 601 outputs, to the operation panel 626, a messageprompting to remove the sheet in a double-sided printing conveyancemalfunction. A message to be output at this time may be, for example,the sentence shown in FIG. 37I or may be a picture. Alternatively, inorder for a user to easily understand necessary operation, an animationmay be displayed on the operation panel 626. A sheet in a conveyancemalfunction is also referred to as first sheet.

In S5321, when the sheet in a conveyance malfunction is removed by theuser, the CPU 601 receives a HIGH signal output from the double-sidedprinting conveying sensor 113, and the process proceeds to S5322.

In S5322, the door (not shown) of the image forming apparatus 20, openedby the user to remove the sheet in a conveyance malfunction, is switchedinto the close position. When the door (not shown) of the image formingapparatus 20 is switched into the close position, the CPU 601 receives aLOW signal output from the open/close sensor for the door (not shown),and the process proceeds to S5323.

In the present embodiment, when the CPU 601 completes the processes ofS5321 and S5322, the CPU 601 detects that jam recovery is complete. Whenthe CPU 601 detects that jam recovery is complete, the CPU 601 starts aprocess of reforming the image formed on the sheet in a conveyancemalfunction onto a new sheet. This process is referred to as reprint. Anew sheet is also referred to as second sheet.

In S5323, when reprint is performed, the CPU 601 returns the process toS5301 and starts a process of reforming the image formed on the sheet ina conveyance malfunction onto a new sheet. At this time, a sheet in aconveyance malfunction is also referred to as fifth sheet, and a newsheet is also referred to as sixth sheet.

In S5323, when a sheet is normally output during the process of S5313but the job is not complete, and the CPU 601 has received information toperform image formation again from the printer controller 213, theprocess returns to S5301. When the job is complete and an image is notformed again, the CPU 601 ends the process.

A printing instruction in a job in the case where a double-sidedprinting conveyance malfunction has occurred is also referred to asfifth printing instruction, and a job in the case where a double-sidedprinting conveyance malfunction has occurred is also referred to asfifth job. A printing instruction that the CPU 601 newly receives fromthe printer controller 213 after a double-sided printing conveyancemalfunction is resolved is also referred to as sixth printinginstruction, and a job that the CPU 601 executes in accordance with aprinting instruction newly received from the printer controller 213 isalso referred to as sixth job.

In the present embodiment, the CPU 601 may advance the process to S5324after S5313 as shown in FIG. 36C and FIG. 36D.

In S5324, when a sheet is normally conveyed to the image forming unitand information about the fact that a LOW signal output from the FD traysheet output sensor 125 is detected a predetermined number of times isstored in the NVRAM 608, the CPU 601 advances the process to S5325.

In S5325, when information about the fact that a double-sided printingconveyance malfunction is detected is stored in the NVRAM 608, the CPU601 deletes, from the NVRAM 608, information about the fact that a sheetfeed conveyance malfunction has occurred, and the process proceeds toS5323.

By executing the processes of S5324 and S5325, it is possible to outputa message to the user in S5302 only just after occurrence of aconveyance malfunction and there is a high possibility that a conveyancemalfunction occurs, and this leads to improvement in usability.

As described above, the CPU 601 switches the FU tray 116 into the openposition and outputs a message prompting to switch the sheet feedingunit from the sheet feeding cassette 100 to the MP tray 140. Byoutputting the message, it is possible to reduce occurrence of adouble-sided printing conveyance malfunction again.

Alternatively, the CPU 601 and an MPU (not shown) including a pluralityof processors, such as multi-cores, may implement the function of theCPU 601 with the plurality of processors.

Summary of Fifteenth Embodiment

As described above, in the present embodiment, control for the CPU 601to detect a conveyance malfunction and reduce occurrence of the sameconveyance malfunction again for three cases where a conveyancemalfunction occurs has been described.

In the present embodiment, the CPU 601 detects whether a sheet outputconveyance malfunction has occurred in accordance with a signal outputfrom the after-fixing paper presence sensor 110. The CPU 601 causes theNVRAM 608 to store information about occurrence of a sheet outputconveyance malfunction. When information about occurrence of a sheetoutput conveyance malfunction is stored in the NVRAM 608, the operationpanel 626 is caused to output a message prompting to switch the FU tray116 into the open position.

In the present embodiment, the CPU 601 detects whether a sheet feedconveyance malfunction has occurred in accordance with a signal outputfrom the after-feeding paper presence sensor 118. The CPU 601 causes theNVRAM 608 to store information about occurrence of a sheet feedconveyance malfunction. When information about occurrence of a sheetfeed conveyance malfunction is stored in the NVRAM 608, the operationpanel 626 is caused to output a message prompting to switch the sheetfeeding section into the open position.

In addition, in the present embodiment, the CPU 601 causes the pair ofFD rollers 112 to convey a sheet having a first image in the secondconveying direction and then detects whether a double-sided printingconveyance malfunction has occurred in accordance with a signal outputfrom the registration sensor 106. The CPU 601 causes the NVRAM 608 tostore information about occurrence of a double-sided printing conveyancemalfunction. When information about occurrence of a double-sidedprinting conveyance malfunction is stored in the NVRAM 608, theoperation panel 626 is caused to output a message prompting to switchthe sheet feeding section and to switch the FU tray 116 into the openposition.

With the above-described function, depending on the status of occurrenceof a conveyance malfunction, a message prompting to switch the conveyingpath is output, so occurrence of a conveyance malfunction is reduced.

Sixteenth Embodiment

In the fifteenth embodiment, the case where the FU tray 116 is manuallyopened or closed by a user has been described. In the presentembodiment, the FU tray 116 may be automatically opened or closed. Whenthe FU tray 116 does not need to be opened or closed, a lockingmechanism capable of locking such that the FU tray 116 is not switchedinto the open state may be provided.

In the present embodiment, control for the CPU 601 to detect a sheetoutput conveyance malfunction and reduce occurrence of the sameconveyance malfunction again will be described.

FIG. 38A is a schematic configuration diagram of the image formingapparatus 20 of the present embodiment. The image forming apparatus 20includes the FU tray solenoid 144, and a lock unit that restricts theopening of the FU tray 116. The FU tray 116 includes a mechanism toautomatically switch into the open state. The image forming apparatus 20is the same as the above-described image forming apparatus 20 shown inFIG. 18 other than the FU tray solenoid 144 and the lock unit, so thedescription thereof is omitted.

FIG. 38B is a block diagram showing the configuration of hardwareconcerned with sheet conveyance control as a software functionimplemented by the printing section 221 of the present embodiment. Thecomponents are the same as those of the block diagram of FIG. 19B otherthan the FU tray solenoid 144 and the FU tray solenoid driving circuit619, so the description thereof is omitted. As shown in FIG. 38B, thedrive of the FU tray solenoid 144 is controlled by the CPU 601 via theFU tray solenoid driving circuit 619 and the I/O port 606.

Lock Unit for FU Tray 116 and Mechanism for Automatically Switching intoOpen State

Hereinafter, the lock unit and the automatic opening/closing mechanismof the image forming apparatus 20 in the present embodiment will bedescribed with reference to FIG. 38C.

The image forming apparatus 20 includes the FU tray solenoid 144, alocking member 145 a that is a mechanical member interlocking with theFU tray solenoid 144, and a locking member 146 with which a pawl 145 bof the locking member 145 a provided for the FU tray 116 interferes, asthe lock unit. The drive of the FU tray solenoid 144 is controlled bythe CPU 601 via the FU tray solenoid driving circuit 619.

When the FU tray solenoid driving circuit 619 is in an off state and theFU tray solenoid 144 is in an off state, the locking member 145 a is ina locked state such that the FU tray 116 is not switched into the openposition as shown in FIG. 38C. At this time, the pawl 145 b of thelocking member 145 a interferes with the locking member 146 to preventthe FU tray 116 from opening as shown in FIG. 38E. FIG. 38E is a viewshowing the main body of the image forming apparatus 20 in the stateshown in FIG. 38C when viewed from vertically above. This state isdefined as steady state.

When the power of the image forming apparatus 20 is turned off, the FUtray solenoid 144 is a self-hold solenoid in the present embodiment inorder to prevent the FU tray 116 from opening. With the self-holdsolenoid, the FU tray solenoid 144 is capable of holding a locked statesuch that the FU tray 116 is not switched into the open position even ina state where no power is supplied.

When the CPU 601 sets the FU tray solenoid driving circuit 619 in the onstate to set the FU tray solenoid 144 in the on state, the lockingmember 145 a pivots, and the pawl 145 b does not interfere with thelocking member 146. Therefore, as shown in FIG. 38D, the FU tray 116switches into the open position by its own weight. When the FU tray 116switches into the open position by its own weight, the FU tray solenoiddriving circuit 619 is set to the off state to set the FU tray solenoid144 to the off state, with the result that the locking member 145 areturns to the position in the steady state as shown in FIG. 38A.

When the FU tray 116 is switched into the close position, a force in thedirection of the arrow as shown in FIG. 38F is applied to the FU tray116 by user's operation. When the locking member 146 contacts with theinclined surface of the pawl 145 b, the locking member 145 a is pushedup by the force applied by the user, and the locking member 145 aeventually returns to the steady state, with the result that the FU tray116 returns to the locked state again.

When the FU tray 116 switches into the open state and the CPU 601detects a HIGH signal output from the FU tray open/close sensor 117, theFU tray solenoid driving circuit 619 may be switched into the off state.With this configuration, the FU tray solenoid 144 may be switched intothe off state by switching the FU tray solenoid driving circuit 619 intothe off state, thus returning the locking member 145 a to the positionin the steady state as shown in FIG. 38A.

Process for Reducing Sheet Output Conveyance Malfunction

In the present embodiment, when a sheet output conveyance malfunctionhas occurred, there is a possibility that the same conveyancemalfunction occurs again. In this case, the CPU 601 releases the lockingmechanism to switch the FU tray 116 into the open position, so it ispossible to reduce occurrence of the same conveyance malfunction again.A sheet output conveyance malfunction is as described in Sheet OutputConveyance Malfunction.

A specific process in the case where there is a possibility that a sheetoutput conveyance malfunction occurs and in the case where a sheetoutput conveyance malfunction has occurred will be described withreference to the flowcharts of FIG. 39A and FIG. 39B. The flowcharts ofFIG. 39A and FIG. 39B are a modification of FIG. 34C and FIG. 34D, andonly S51001 and S51002 are different.

Initially, the CPU 601 receives, from the printer controller 213, aprinting instruction including information about a series of printingoperation to cause the sheet feeding unit to feed a sheet and cause theimage forming unit to form an image on the sheet and output the sheet.The CPU 601 starts a job in accordance with the printing instruction.

In S5101, when information about occurrence of a sheet output conveyancemalfunction is stored in the NVRAM 608, the CPU 601 advances the processto S5102. In S5101, when information about occurrence of a sheet outputconveyance malfunction is not stored in the NVRAM 608, the CPU 601starts the printing operation in a state where the FU tray 116 isclosed, and the process proceeds to S51001.

In S51001, the CPU 601 releases the lock unit that locks such that theFU tray 116 is not switched into the open state. The CPU 601 sets the FUtray solenoid driving circuit 619 to the on state to set the FU traysolenoid 144 to the on state, with the result that the locking member145 a is pivoted to switch the FU tray 116 into the open position, andthen the process proceeds to S51002. With this function, it is possibleto reduce occurrence of a conveyance malfunction due to the fact thatthe FU tray 116 is in the close position, and this leads to improvementin usability.

The CPU 601 may output, to the operation panel 626, a message promptingto switch the FU tray 116 into the open position before releasing thelock unit.

In addition, when the CPU 601 causes the NVRAM 608 to store informationabout occurrence of a sheet output conveyance malfunction, the CPU 601may cause the NVRAM 608 to store information for releasing the lock unitthat locks such that the FU tray 116 is not switched into the openstate.

In S51002, when the FU tray 116 opens and the CPU 601 receives a HIGHsignal output from the FU tray open/close sensor 117, the processproceeds to S5104.

Summary of Sixteenth Embodiment

As described above, in the present embodiment, control for the CPU 601to detect a conveyance malfunction and reduce occurrence of a sheetoutput conveyance malfunction again for three cases where a sheet outputconveyance malfunction occurs has been described.

In the present embodiment, the CPU 601 detects whether a sheet outputconveyance malfunction has occurred in accordance with a signal outputfrom the after-fixing paper presence sensor 110. The CPU 601 causes theNVRAM 608 to store information about occurrence of a sheet outputconveyance malfunction. When information about occurrence of a sheetoutput conveyance malfunction is stored in the NVRAM 608, the FU tray116 is switched into the open position by releasing the lock unit thatlocks such that the FU tray 116 is not switched into the open state.

With the above-described function, according to the status of occurrenceof a sheet output conveyance malfunction, even when the FU tray 116 isnot operated by a user, the FU tray 116 can be switched into the openposition, so it is possible to reduce occurrence of a conveyancemalfunction.

As described above, according to the embodiments of the presentdisclosure, it is possible to prompt to switch the open/closed state ofthe FU tray in accordance with an input type of sheet beforetransmitting image information to the image forming apparatus.

Other Embodiments

Embodiment(s) of the present disclosure can also be realized by acomputer of a system or apparatus that reads out and executes computerexecutable instructions (e.g., one or more programs) recorded on astorage medium (which may also be referred to more fully as a‘non-transitory computer-readable storage medium’) to perform thefunctions of one or more of the above-described embodiment(s) and/orthat includes one or more circuits (e.g., application specificintegrated circuit (ASIC)) for performing the functions of one or moreof the above-described embodiment(s), and by a method performed by thecomputer of the system or apparatus by, for example, reading out andexecuting the computer executable instructions from the storage mediumto perform the functions of one or more of the above-describedembodiment(s) and/or controlling the one or more circuits to perform thefunctions of one or more of the above-described embodiment(s). Thecomputer may comprise one or more processors (e.g., central processingunit (CPU), micro processing unit (MPU)) and may include a network ofseparate computers or separate processors to read out and execute thecomputer executable instructions. The computer executable instructionsmay be provided to the computer, for example, from a network or thestorage medium. The storage medium may include, for example, one or moreof a hard disk, a random-access memory (RAM), a read only memory (ROM),a storage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present disclosure has been described with reference toexemplary embodiments, it is to be understood that the disclosure is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

What is claimed is:
 1. An information processing method for aninformation processing apparatus, wherein the information processingapparatus is configured to communicate with an image forming apparatushaving an image forming unit configured to form an image on a sheet, andhaving first and second sheet output sections, each configured toreceive output of the sheet having the image formed on the sheet, andwherein, when conveyed along a first sheet output conveying path, thesheet is output to the first sheet output section so that the imagefaces downward and, when conveyed along a second sheet output conveyingpath, the sheet is output to the second sheet output section so that theimage faces upward, the information processing method comprising:inputting a type of sheet as an inputting process; transmitting imageinformation to the image forming apparatus; and outputting, as a firstoutput, a first message when the input type of sheet is a sheetrecommended to be output to the second sheet output section, wherein thefirst message is to give a notification that the input type of sheet isa sheet recommended to be output to the second sheet output section andto inquire about whether the input type of sheet is to be output to thefirst sheet output section or the second sheet output section before theimage information is transmitted to the image forming apparatus.
 2. Theinformation processing method according to claim 1, wherein aninstruction to automatically switch the second sheet output section intoan open state is transmitted to the image forming apparatus in a casewhere the input type of sheet is the sheet recommended to be output tothe second sheet output section and outputting the input type of sheetto the second sheet output section is selected in response to the firstmessage.
 3. The information processing method according to claim 1,wherein the image forming apparatus includes a first sheet feeding uniton which a sheet is stacked and a second sheet feeding unit on which asheet is stacked, wherein the first sheet feeding unit is configured toconvey the sheet stacked on the first sheet feeding unit to the imageforming unit via a first sheet conveying path in such a way that anupper surface when the sheet is stacked on the first sheet feeding unitfaces down, wherein the second sheet feeding unit is configured toconvey the sheet stacked on the second sheet feeding unit to the imageforming unit via a second sheet conveying path in such a way that anupper surface when the sheet is stacked on the second sheet feeding unitfaces up, and wherein the second sheet feeding unit is selected as asheet feeding unit and a message to prompt stacking of a sheet on thesecond sheet feeding unit is output in response to inputting the type ofsheet recommended to be output to the second sheet output section. 4.The information processing method according to claim 1, wherein inaddition to inputting the type of sheet, inputting includes inputtingsingle-sided printing or double-sided printing.
 5. The informationprocessing method according to claim 1, wherein the second sheet outputsection is capable of being switched between a closed position and anopen position, and wherein the second sheet output section serves as aguiding portion configured to guide the sheet to the first sheet outputsection at the closed position, and serves as a sheet output sectionconfigured not to guide the sheet to the first sheet output section butto be capable of stacking the sheet at the open position.
 6. Theinformation processing method according to claim 5, further comprisingoutputting, as a second output, a second message to prompt to switch thesecond sheet output section into the closed position before the imageinformation is transmitted to the image forming apparatus in a casewhere outputting the input type of sheet to the first sheet outputsection is selected in response to the first message.
 7. The informationprocessing method according to claim 6, further comprising acquiringinformation indicating whether the second sheet output section is openedor closed in a case where the second message is output in the secondoutput, wherein outputting the second output continues until informationindicating that the second sheet output section is closed is acquiredafter the second output outputs the second message.
 8. The informationprocessing method according to claim 5, further comprising outputting,as a second output, a second message to prompt to switch the secondsheet output section into the open position before the image informationis transmitted to the image forming apparatus in a case where outputtingthe input type of sheet to the second sheet output section is selectedin response to the first message.
 9. The information processing methodaccording to claim 8, further comprising acquiring informationindicating whether the second sheet output section is opened or closedin a case where the second message is output in the second output,wherein outputting the second output continues until informationindicating that the second sheet output section is opened is acquiredafter the second output outputs the second message.
 10. The informationprocessing method according to claim 8, wherein, in outputting the firstoutput and the second output, the first message and the second messageare output to cover a part of a screen for inputting the type of sheetwhere the screen for inputting the type of sheet is closed in a casewhere the second message is closed.
 11. The information processingmethod according to claim 1, further comprising outputting, as a thirdoutput, a message to give a notification that the input type of sheet isa sheet not recommended for double-sided printing and to give anotification to change double-sided printing to single-sided printing ina case where the input type of sheet is the sheet recommended to beoutput to the second sheet output section and double-sided printing isinput.
 12. The information processing method according to claim 1,further comprising outputting, as a second output, a second message,wherein, during the first output and the second output, the informationprocessing apparatus does not transmit the image information to theimage forming apparatus in outputting the first message and inoutputting the second message.
 13. A non-transitory computer-readablestorage medium storing a program causing a computer to execute theinformation processing method according to claim
 1. 14. An informationprocessing apparatus, wherein the information processing apparatus isconfigured to communicate with an image forming apparatus having animage forming unit configured to form an image on a sheet, and havingfirst and second sheet output sections, each configured to receiveoutput of the sheet having the image formed on the sheet, and wherein,when conveyed along a first sheet output conveying path, the sheet isoutput to the first sheet output section so that the image facesdownward and, when conveyed along a second sheet output conveying path,the sheet is output to the second sheet output section so that the imagefaces upward, the information processing apparatus comprising: an inputunit configured to input a type of sheet as an inputting process; atransmission unit configured to transmit image information to the imageforming apparatus; and a first output unit configured to output a firstmessage when the input type of sheet is a sheet recommended to be outputto the second sheet output section, wherein the first message is to givea notification that the input type of sheet is a sheet recommended to beoutput to the second sheet output section and to inquire about whetherthe input type of sheet is to be output to the first sheet outputsection or the second sheet output section before the image informationis transmitted to the image forming apparatus.
 15. The informationprocessing apparatus according to claim 14, wherein the transmissionunit transmits an instruction to automatically switch the second sheetoutput section into an open state to the image forming apparatus in acase where the input type of sheet is the sheet recommended to be outputto the second sheet output section and outputting the input type ofsheet to the second sheet output section is selected in response to thefirst message, or the transmission unit transmits an instruction toautomatically switch the second sheet output section into the closestate to the image forming apparatus in a case where the input type ofsheet is the sheet recommended to be output to the second sheet outputsection and outputting the input type of sheet to the first sheet outputsection is selected in response to the first message.
 16. Theinformation processing apparatus according to claim 14, wherein theimage forming apparatus includes a first sheet feeding unit on which asheet is stacked and a second sheet feeding unit on which a sheet isstacked, wherein the first sheet feeding unit is configured to conveythe sheet stacked on the first sheet feeding unit to the image formingunit via a first sheet conveying path in such a way that an uppersurface when the sheet is stacked on the first sheet feeding unit facesdown, wherein the second sheet feeding unit is configured to convey thesheet stacked on the second sheet feeding unit to the image forming unitvia a second sheet conveying path in such a way that an upper surfacewhen the sheet is stacked on the second sheet feeding unit faces up, andwherein the second sheet feeding unit is selected as a sheet feedingunit and a message to prompt stacking of a sheet on the second sheetfeeding unit is output in response to input, by the input unit, of thetype of sheet recommended to be output to the second sheet outputsection.
 17. The information processing apparatus according to claim 14,wherein, in addition to inputting the type of sheet, the input unitinputs single-sided printing or double-sided printing.
 18. Theinformation processing apparatus according to claim 14, wherein thesecond sheet output section is capable of being switched between aclosed position and an open position, and wherein the second sheetoutput section serves as a guiding portion configured to guide the sheetto the first sheet output section at the closed position, and serves asa sheet output section configured not to guide the sheet to the firstsheet output section but to be capable of stacking the sheet at the openposition.
 19. The information processing apparatus according to claim18, further comprising a second output unit configured to output asecond message to prompt to switch the second sheet output section intothe closed position before the image information is transmitted to theimage forming apparatus in a case where outputting the input type ofsheet to the first sheet output section is selected in response to thefirst message.
 20. The information processing apparatus according toclaim 19, further comprising an acquisition unit configured to acquireinformation indicating whether the second sheet output section is openedor closed in a case where the second output unit outputs the secondmessage, wherein the second output unit continues outputting the secondmessage until the acquisition unit acquires information indicating thatthe second sheet output section is closed after the second output unitoutputs the second message.
 21. The information processing apparatusaccording to claim 18, further comprising a second output unitconfigured to output a second message to prompt to switch the secondsheet output section into the open position before the image informationis transmitted to the image forming apparatus in a case where outputtingthe input type of sheet to the second sheet output section is selectedin response to the first message.
 22. The information processingapparatus according to claim 21, further comprising an acquisition unitconfigured to acquire information indicating whether the second sheetoutput section is opened or closed in a case where the second outputunit outputs the second message, wherein the second output unitcontinues outputting the second message until the acquisition unitacquires information indicating that the second sheet output section isopened after the second output unit outputs the second message.
 23. Theinformation processing apparatus according to claim 21, wherein theimage information is not transmitted to the image forming apparatuswhile the first output unit is outputting the first message and whilethe second output unit is outputting the second message.
 24. Theinformation processing apparatus according to claim 14, furthercomprising a third output unit configured to output a message to give anotification that the input type of sheet is a sheet not recommended fordouble-sided printing and to give a notification to change double-sidedprinting to single-sided printing in a case where the input type ofsheet is the sheet recommended to be output to the second sheet outputsection and double-sided printing is input.
 25. An image formingapparatus to communicate with an information processing apparatusincluding a receiving unit configured to receive image informationincluding a type of sheet, the image forming apparatus comprising: animage forming unit configured to form an image on a sheet; a first sheetoutput section configured to receive output of the sheet having theimage formed by the image forming unit such that the image formed by theimage forming unit faces down after being conveyed along a first sheetoutput conveying path; a second sheet output section configured toreceive output of the sheet having the image formed by the image formingunit such that the image formed by the image forming unit faces up as adirection opposite of down after being conveyed along a second sheetoutput conveying path; and a first output unit configured to output afirst message to give a notification that the type of sheet received bythe receiving unit is a sheet recommended to be output to the secondsheet output section and, in a case where the received type of sheet isa sheet recommended to be output to the second sheet output section, toinquire about whether the received type of sheet is to be output to thefirst sheet output section or the second sheet output section.
 26. Theimage forming apparatus according to claim 25, wherein the second sheetoutput section is capable of being switched between a closed positionand an open position, and wherein the second sheet output section servesas a guiding portion configured to guide the sheet to the first sheetoutput section at the closed position, and serves as a sheet outputsection configured not to guide the sheet to the first sheet outputsection but configured to stack the sheet at the open position.
 27. Theimage forming apparatus according to claim 26, further comprising asecond output unit configured to output a second message to prompt toswitch the second sheet output section into the open position before theimage information is transmitted to the image forming apparatus in acase where outputting the received type of sheet to the second sheetoutput section is selected in response to the first message.
 28. Theimage forming apparatus according to claim 27, further comprising adetection unit configured to detect whether the second sheet outputsection is opened or closed in a case where the second output unitoutputs the second message, wherein the second output unit continuesoutputting the second message until the detection unit detects that thesecond sheet output section is opened after the second output unitoutputs the second message.
 29. The image forming apparatus according toclaim 26, further comprising a second output unit configured to output asecond message to prompt to switch the second sheet output section intothe closed position before the image information is transmitted to theimage forming apparatus in a case where outputting the received type ofsheet to the first sheet output section is selected in response to thefirst message.
 30. The image forming apparatus according to claim 29,further comprising a detection unit configured to detect whether thesecond sheet output section is opened or closed in a case where thesecond output unit outputs the second message, wherein the second outputunit continues outputting the second message until the detection unitdetects that the second sheet output section is closed after the secondoutput unit outputs the second message.
 31. The image forming apparatusaccording to claim 25, wherein the second sheet output section isautomatically switched into an open state in a case where the receivedtype of sheet is the sheet recommended to be output to the second sheetoutput section and outputting the received type of sheet to the secondsheet output section is selected in response to the first message, orthe second sheet output section is automatically switched into the closestate in a case where the received type of sheet is the sheetrecommended to be output to the second sheet output section andoutputting the received type of sheet to the first sheet output sectionis selected in response to the first message.
 32. An informationprocessing system comprising: an image forming unit configured to forman image on a sheet; a first sheet output section configured to receiveoutput of the sheet having the image formed by the image forming unitsuch that the image formed by the image forming unit faces down afterbeing conveyed along a first sheet output conveying path; a second sheetoutput section configured to receive output of the sheet having theimage formed by the image forming unit such that the image formed by theimage forming unit faces up as a direction opposite of down after beingconveyed along a second sheet output conveying path; an input unitconfigured to input a type of sheet; and a first output unit configuredto output a first message to give a notification that the input type ofsheet is a sheet recommended to be output to the second sheet outputsection and, in a case where the input type of sheet is a sheetrecommended to be output to the second sheet output section, to inquireabout whether the input type of sheet is to be output to the first sheetoutput section or the second sheet output section.
 33. The informationprocessing method according to claim 1, wherein a radius of curvature ofthe second sheet output conveying path is greater than a radius ofcurvature of the first sheet output conveying path.